Moved the majority of WebGL functionality into WebGLRenderingContextBase

Source/core/html/canvas/WebGLRenderingContextBase.cpp

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
-#include "core/html/canvas/WebGLRenderingContext.h"
+#include "core/html/canvas/WebGLRenderingContextBase.h"
 
 #include "RuntimeEnabledFeatures.h"
 #include "bindings/v8/ExceptionMessages.h"
 #include "bindings/v8/ExceptionState.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/fetch/ImageResource.h"
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLImageElement.h"
 #include "core/html/HTMLVideoElement.h"
 #include "core/html/ImageData.h"
@@ skipping 43 matching lines @@
 #include "wtf/PassOwnPtr.h"
 #include "wtf/Uint32Array.h"
 #include "wtf/text/StringBuilder.h"
 
 namespace WebCore {
 
 const double secondsBetweenRestoreAttempts = 1.0;
 const int maxGLErrorsAllowedToConsole = 256;
 const unsigned maxGLActiveContexts = 16;
 
-Vector<WebGLRenderingContext*>& WebGLRenderingContext::activeContexts()
+Vector<WebGLRenderingContextBase*>& WebGLRenderingContextBase::activeContexts()
 {
-    DEFINE_STATIC_LOCAL(Vector<WebGLRenderingContext*>, activeContexts, ());
+    DEFINE_STATIC_LOCAL(Vector<WebGLRenderingContextBase*>, activeContexts, ());
     return activeContexts;
 }
 
-Vector<WebGLRenderingContext*>& WebGLRenderingContext::forciblyEvictedContexts()
+Vector<WebGLRenderingContextBase*>& WebGLRenderingContextBase::forciblyEvictedContexts()
 {
-    DEFINE_STATIC_LOCAL(Vector<WebGLRenderingContext*>, forciblyEvictedContexts, ());
+    DEFINE_STATIC_LOCAL(Vector<WebGLRenderingContextBase*>, forciblyEvictedContexts, ());
     return forciblyEvictedContexts;
 }
 
-void WebGLRenderingContext::forciblyLoseOldestContext(const String& reason)
+void WebGLRenderingContextBase::forciblyLoseOldestContext(const String& reason)
 {
     size_t candidateID = oldestContextIndex();
     if (candidateID >= activeContexts().size())
         return;
 
-    WebGLRenderingContext* candidate = activeContexts()[candidateID];
+    WebGLRenderingContextBase* candidate = activeContexts()[candidateID];
 
     activeContexts().remove(candidateID);
 
     candidate->printWarningToConsole(reason);
     InspectorInstrumentation::didFireWebGLWarning(candidate->canvas());
 
     // This will call deactivateContext once the context has actually been lost.
-    candidate->forceLostContext(WebGLRenderingContext::SyntheticLostContext);
+    candidate->forceLostContext(WebGLRenderingContextBase::SyntheticLostContext);
 }
 
-size_t WebGLRenderingContext::oldestContextIndex()
+size_t WebGLRenderingContextBase::oldestContextIndex()
 {
     if (!activeContexts().size())
         return maxGLActiveContexts;
 
-    WebGLRenderingContext* candidate = activeContexts().first();
+    WebGLRenderingContextBase* candidate = activeContexts().first();
     size_t candidateID = 0;
     for (size_t ii = 1; ii < activeContexts().size(); ++ii) {
-        WebGLRenderingContext* context = activeContexts()[ii];
+        WebGLRenderingContextBase* context = activeContexts()[ii];
         if (context->webGraphicsContext3D() && candidate->webGraphicsContext3D() && context->webGraphicsContext3D()->lastFlushID() < candidate->webGraphicsContext3D()->lastFlushID()) {
             candidate = context;
             candidateID = ii;
         }
     }
 
     return candidateID;
 }
 
-IntSize WebGLRenderingContext::oldestContextSize()
+IntSize WebGLRenderingContextBase::oldestContextSize()
 {
     IntSize size;
 
     size_t candidateID = oldestContextIndex();
     if (candidateID < activeContexts().size()) {
-        WebGLRenderingContext* candidate = activeContexts()[candidateID];
+        WebGLRenderingContextBase* candidate = activeContexts()[candidateID];
         size.setWidth(candidate->drawingBufferWidth());
         size.setHeight(candidate->drawingBufferHeight());
     }
 
     return size;
 }
 
-void WebGLRenderingContext::activateContext(WebGLRenderingContext* context)
+void WebGLRenderingContextBase::activateContext(WebGLRenderingContextBase* context)
 {
     unsigned removedContexts = 0;
     while (activeContexts().size() >= maxGLActiveContexts && removedContexts < maxGLActiveContexts) {
         forciblyLoseOldestContext("WARNING: Too many active WebGL contexts. Oldest context will be lost.");
         removedContexts++;
     }
 
     if (!activeContexts().contains(context))
         activeContexts().append(context);
 }
 
-void WebGLRenderingContext::deactivateContext(WebGLRenderingContext* context, bool addToEvictedList)
+void WebGLRenderingContextBase::deactivateContext(WebGLRenderingContextBase* context, bool addToEvictedList)
 {
     size_t position = activeContexts().find(context);
     if (position != WTF::kNotFound)
         activeContexts().remove(position);
 
     if (addToEvictedList && !forciblyEvictedContexts().contains(context))
         forciblyEvictedContexts().append(context);
 }
 
-void WebGLRenderingContext::willDestroyContext(WebGLRenderingContext* context)
+void WebGLRenderingContextBase::willDestroyContext(WebGLRenderingContextBase* context)
 {
     size_t position = forciblyEvictedContexts().find(context);
     if (position != WTF::kNotFound)
         forciblyEvictedContexts().remove(position);
 
     deactivateContext(context, false);
 
     // Try to re-enable the oldest inactive contexts.
     while(activeContexts().size() < maxGLActiveContexts && forciblyEvictedContexts().size()) {
-        WebGLRenderingContext* evictedContext = forciblyEvictedContexts().first();
+        WebGLRenderingContextBase* evictedContext = forciblyEvictedContexts().first();
         if (!evictedContext->m_restoreAllowed) {
             forciblyEvictedContexts().remove(0);
             continue;
         }
 
         IntSize desiredSize = evictedContext->m_drawingBuffer->adjustSize(evictedContext->clampedCanvasSize());
 
         // If there's room in the pixel budget for this context, restore it.
         if (!desiredSize.isEmpty()) {
             forciblyEvictedContexts().remove(0);
             evictedContext->forceRestoreContext();
             activeContexts().append(evictedContext);
         }
         break;
     }
 }
 
 class WebGLRenderingContextEvictionManager : public ContextEvictionManager {
 public:
     void forciblyLoseOldestContext(const String& reason) {
-        WebGLRenderingContext::forciblyLoseOldestContext(reason);
+        WebGLRenderingContextBase::forciblyLoseOldestContext(reason);
     };
     IntSize oldestContextSize() {
-        return WebGLRenderingContext::oldestContextSize();
+        return WebGLRenderingContextBase::oldestContextSize();
     };
 };
 
 namespace {
 
     class ScopedDrawingBufferBinder {
     public:
         ScopedDrawingBufferBinder(DrawingBuffer* drawingBuffer, WebGLFramebuffer* framebufferBinding)
             : m_drawingBuffer(drawingBuffer)
             , m_framebufferBinding(framebufferBinding)
@@ skipping 232 matching lines @@
             // want or need to just emit a space per character to try
             // to preserve column numbers for debugging purposes.
             break;
         }
     }
 } // namespace anonymous
 
 class WebGLRenderingContextLostCallback : public blink::WebGraphicsContext3D::WebGraphicsContextLostCallback {
     WTF_MAKE_FAST_ALLOCATED;
 public:
-    explicit WebGLRenderingContextLostCallback(WebGLRenderingContext* cb) : m_context(cb) { }
-    virtual void onContextLost() { m_context->forceLostContext(WebGLRenderingContext::RealLostContext); }
+    explicit WebGLRenderingContextLostCallback(WebGLRenderingContextBase* cb) : m_context(cb) { }
+    virtual void onContextLost() { m_context->forceLostContext(WebGLRenderingContextBase::RealLostContext); }
     virtual ~WebGLRenderingContextLostCallback() {}
 private:
-    WebGLRenderingContext* m_context;
+    WebGLRenderingContextBase* m_context;
 };
 
 class WebGLRenderingContextErrorMessageCallback : public blink::WebGraphicsContext3D::WebGraphicsErrorMessageCallback {
     WTF_MAKE_FAST_ALLOCATED;
 public:
-    explicit WebGLRenderingContextErrorMessageCallback(WebGLRenderingContext* cb) : m_context(cb) { }
+    explicit WebGLRenderingContextErrorMessageCallback(WebGLRenderingContextBase* cb) : m_context(cb) { }
     virtual void onErrorMessage(const blink::WebString& message, blink::WGC3Dint)
     {
         if (m_context->m_synthesizedErrorsToConsole)
             m_context->printGLErrorToConsole(message);
         InspectorInstrumentation::didFireWebGLErrorOrWarning(m_context->canvas(), message);
     }
     virtual ~WebGLRenderingContextErrorMessageCallback() { }
 private:
-    WebGLRenderingContext* m_context;
+    WebGLRenderingContextBase* m_context;
 };
 
-PassOwnPtr<WebGLRenderingContext> WebGLRenderingContext::create(HTMLCanvasElement* canvas, WebGLContextAttributes* attrs)
-{
-    Document& document = canvas->document();
-    Frame* frame = document.frame();
-    if (!frame)
-        return nullptr;
-    Settings* settings = frame->settings();
-
-    // The FrameLoaderClient might block creation of a new WebGL context despite the page settings; in
-    // particular, if WebGL contexts were lost one or more times via the GL_ARB_robustness extension.
-    if (!frame->loader().client()->allowWebGL(settings && settings->webGLEnabled())) {
-        canvas->dispatchEvent(WebGLContextEvent::create(EventTypeNames::webglcontextcreationerror, false, true, "Web page was not allowed to create a WebGL context."));
-        return nullptr;
-    }
-
-    // The only situation that attrs is null is through Document::getCSSCanvasContext().
-    RefPtr<WebGLContextAttributes> defaultAttrs;
-    if (!attrs) {
-        defaultAttrs = WebGLContextAttributes::create();
-        attrs = defaultAttrs.get();
-    }
-    blink::WebGraphicsContext3D::Attributes attributes = attrs->attributes(document.topDocument()->url().string(), settings);
-    OwnPtr<blink::WebGraphicsContext3D> context = adoptPtr(blink::Platform::current()->createOffscreenGraphicsContext3D(attributes));
-    if (!context || !context->makeContextCurrent()) {
-        canvas->dispatchEvent(WebGLContextEvent::create(EventTypeNames::webglcontextcreationerror, false, true, "Could not create a WebGL context."));
-        return nullptr;
-    }
-
-    Extensions3DUtil extensionsUtil(context.get());
-    if (extensionsUtil.supportsExtension("GL_EXT_debug_marker"))
-        context->pushGroupMarkerEXT("WebGLRenderingContext");
-
-    OwnPtr<WebGLRenderingContext> renderingContext = adoptPtr(new WebGLRenderingContext(canvas, context.release(), attrs));
-    renderingContext->suspendIfNeeded();
-
-    if (renderingContext->m_drawingBuffer->isZeroSized()) {
-        canvas->dispatchEvent(WebGLContextEvent::create(EventTypeNames::webglcontextcreationerror, false, true, "Could not create a WebGL context."));
-        return nullptr;
-    }
-
-    return renderingContext.release();
-}
-
-WebGLRenderingContext::WebGLRenderingContext(HTMLCanvasElement* passedCanvas, PassOwnPtr<blink::WebGraphicsContext3D> context, WebGLContextAttributes* requestedAttributes)
+WebGLRenderingContextBase::WebGLRenderingContextBase(HTMLCanvasElement* passedCanvas, PassOwnPtr<blink::WebGraphicsContext3D> context, WebGLContextAttributes* requestedAttributes)
     : CanvasRenderingContext(passedCanvas)
     , ActiveDOMObject(&passedCanvas->document())
     , m_context(context)
     , m_drawingBuffer(nullptr)
-    , m_dispatchContextLostEventTimer(this, &WebGLRenderingContext::dispatchContextLostEvent)
+    , m_dispatchContextLostEventTimer(this, &WebGLRenderingContextBase::dispatchContextLostEvent)
     , m_restoreAllowed(false)
-    , m_restoreTimer(this, &WebGLRenderingContext::maybeRestoreContext)
+    , m_restoreTimer(this, &WebGLRenderingContextBase::maybeRestoreContext)
     , m_generatedImageCache(4)
     , m_contextLost(false)
     , m_contextLostMode(SyntheticLostContext)
     , m_requestedAttributes(requestedAttributes->clone())
     , m_synthesizedErrorsToConsole(true)
     , m_numGLErrorsToConsoleAllowed(maxGLErrorsAllowedToConsole)
     , m_multisamplingAllowed(false)
     , m_multisamplingObserverRegistered(false)
     , m_onePlusMaxEnabledAttribIndex(0)
     , m_onePlusMaxNonDefaultTextureUnit(0)
@@ skipping 11 matching lines @@
 
     // Create the DrawingBuffer and initialize the platform layer.
     DrawingBuffer::PreserveDrawingBuffer preserve = requestedAttributes->preserveDrawingBuffer() ? DrawingBuffer::Preserve : DrawingBuffer::Discard;
     m_drawingBuffer = DrawingBuffer::create(m_context.get(), clampedCanvasSize(), preserve, contextEvictionManager.release());
 
     if (!m_drawingBuffer->isZeroSized()) {
         m_drawingBuffer->bind();
         setupFlags();
         initializeNewContext();
     }
-
-    // Register extensions.
-    static const char* const webkitPrefix[] = { "WEBKIT_", 0, };
-    static const char* const bothPrefixes[] = { "", "WEBKIT_", 0, };
-
-    registerExtension<ANGLEInstancedArrays>(m_angleInstancedArrays);
-    registerExtension<EXTTextureFilterAnisotropic>(m_extTextureFilterAnisotropic, ApprovedExtension, bothPrefixes);
-    registerExtension<OESElementIndexUint>(m_oesElementIndexUint);
-    registerExtension<OESStandardDerivatives>(m_oesStandardDerivatives);
-    registerExtension<OESTextureFloat>(m_oesTextureFloat);
-    registerExtension<OESTextureFloatLinear>(m_oesTextureFloatLinear);
-    registerExtension<OESTextureHalfFloat>(m_oesTextureHalfFloat);
-    registerExtension<OESTextureHalfFloatLinear>(m_oesTextureHalfFloatLinear);
-    registerExtension<OESVertexArrayObject>(m_oesVertexArrayObject);
-    registerExtension<WebGLCompressedTextureATC>(m_webglCompressedTextureATC, PrefixedExtension, webkitPrefix);
-    registerExtension<WebGLCompressedTexturePVRTC>(m_webglCompressedTexturePVRTC, PrefixedExtension, webkitPrefix);
-    registerExtension<WebGLCompressedTextureS3TC>(m_webglCompressedTextureS3TC, ApprovedExtension, bothPrefixes);
-    registerExtension<WebGLDepthTexture>(m_webglDepthTexture, ApprovedExtension, bothPrefixes);
-    registerExtension<WebGLDrawBuffers>(m_webglDrawBuffers);
-    registerExtension<WebGLLoseContext>(m_webglLoseContext, ApprovedExtension, bothPrefixes);
-
-    // Register draft extensions.
-    registerExtension<EXTFragDepth>(m_extFragDepth, DraftExtension);
-
-    // Register privileged extensions.
-    registerExtension<WebGLDebugRendererInfo>(m_webglDebugRendererInfo, WebGLDebugRendererInfoExtension);
-    registerExtension<WebGLDebugShaders>(m_webglDebugShaders, PrivilegedExtension);
 }
 
-void WebGLRenderingContext::initializeNewContext()
+void WebGLRenderingContextBase::initializeNewContext()
 {
     ASSERT(!isContextLost());
     m_needsUpdate = true;
     m_markedCanvasDirty = false;
     m_activeTextureUnit = 0;
     m_packAlignment = 4;
     m_unpackAlignment = 4;
     m_unpackFlipY = false;
     m_unpackPremultiplyAlpha = false;
     m_unpackColorspaceConversion = GC3D_BROWSER_DEFAULT_WEBGL;
@@ skipping 57 matching lines @@
 
     m_contextLostCallbackAdapter = adoptPtr(new WebGLRenderingContextLostCallback(this));
     m_errorMessageCallbackAdapter = adoptPtr(new WebGLRenderingContextErrorMessageCallback(this));
 
     m_context->setContextLostCallback(m_contextLostCallbackAdapter.get());
     m_context->setErrorMessageCallback(m_errorMessageCallbackAdapter.get());
 
     // This ensures that the context has a valid "lastFlushID" and won't be mistakenly identified as the "least recently used" context.
     m_context->flush();
 
+    for (int i = 0; i < WebGLExtensionNameCount; ++i)
+        m_extensionEnabled[i] = false;
+
     activateContext(this);
 }
 
-void WebGLRenderingContext::setupFlags()
+void WebGLRenderingContextBase::setupFlags()
 {
     ASSERT(m_context);
     if (Page* p = canvas()->document().page()) {
         m_synthesizedErrorsToConsole = p->settings().webGLErrorsToConsoleEnabled();
 
         if (!m_multisamplingObserverRegistered && m_requestedAttributes->antialias()) {
             m_multisamplingAllowed = m_drawingBuffer->multisample();
             p->addMultisamplingChangedObserver(this);
             m_multisamplingObserverRegistered = true;
         }
     }
 
     m_isGLES2NPOTStrict = !extensionsUtil()->isExtensionEnabled("GL_OES_texture_npot");
     m_isDepthStencilSupported = extensionsUtil()->isExtensionEnabled("GL_OES_packed_depth_stencil");
 }
 
-bool WebGLRenderingContext::allowPrivilegedExtensions() const
+bool WebGLRenderingContextBase::allowPrivilegedExtensions() const
 {
     if (Page* p = canvas()->document().page())
         return p->settings().privilegedWebGLExtensionsEnabled();
     return false;
 }
 
-bool WebGLRenderingContext::allowWebGLDebugRendererInfo() const
+bool WebGLRenderingContextBase::allowWebGLDebugRendererInfo() const
 {
     return true;
 }
 
-void WebGLRenderingContext::addCompressedTextureFormat(GLenum format)
+void WebGLRenderingContextBase::addCompressedTextureFormat(GLenum format)
 {
     if (!m_compressedTextureFormats.contains(format))
         m_compressedTextureFormats.append(format);
 }
 
-void WebGLRenderingContext::removeAllCompressedTextureFormats()
+void WebGLRenderingContextBase::removeAllCompressedTextureFormats()
 {
     m_compressedTextureFormats.clear();
 }
 
-WebGLRenderingContext::~WebGLRenderingContext()
+// Helper function for V8 bindings to identify what version of WebGL a CanvasRenderingContext supports.
+unsigned WebGLRenderingContextBase::getWebGLVersion(const CanvasRenderingContext* context)
+{
+    if (!context->is3d())
+        return 0;
+    return static_cast<const WebGLRenderingContextBase*>(context)->version();
+}
+
+WebGLRenderingContextBase::~WebGLRenderingContextBase()
 {
     // Remove all references to WebGLObjects so if they are the last reference
     // they will be freed before the last context is removed from the context group.
     m_boundArrayBuffer = nullptr;
     m_defaultVertexArrayObject = nullptr;
     m_boundVertexArrayObject = nullptr;
     m_vertexAttrib0Buffer = nullptr;
     m_currentProgram = nullptr;
     m_framebufferBinding = nullptr;
     m_renderbufferBinding = nullptr;
 
     for (size_t i = 0; i < m_textureUnits.size(); ++i) {
-        m_textureUnits[i].m_texture2DBinding = nullptr;
-        m_textureUnits[i].m_textureCubeMapBinding = nullptr;
+      m_textureUnits[i].m_texture2DBinding = nullptr;
+      m_textureUnits[i].m_textureCubeMapBinding = nullptr;
     }
 
     m_blackTexture2D = nullptr;
     m_blackTextureCubeMap = nullptr;
 
     detachAndRemoveAllObjects();
 
     // release all extensions
     for (size_t i = 0; i < m_extensions.size(); ++i)
         delete m_extensions[i];
 
     // Context must be removed from the group prior to the destruction of the
     // WebGraphicsContext3D, otherwise shared objects may not be properly deleted.
     m_contextGroup->removeContext(this);
 
     destroyContext();
 
     if (m_multisamplingObserverRegistered) {
         Page* page = canvas()->document().page();
         if (page)
             page->removeMultisamplingChangedObserver(this);
     }
 
     willDestroyContext(this);
 }
 
-void WebGLRenderingContext::destroyContext()
+void WebGLRenderingContextBase::destroyContext()
 {
     m_contextLost = true;
 
     // The drawing buffer holds a context reference. It must also be destroyed
     // in order for the context to be released.
     m_drawingBuffer->releaseResources();
 
     m_extensionsUtil.clear();
 
     if (m_context) {
         m_context->setContextLostCallback(0);
         m_context->setErrorMessageCallback(0);
         m_context.clear();
     }
 }
 
-void WebGLRenderingContext::markContextChanged()
+void WebGLRenderingContextBase::markContextChanged()
 {
     if (m_framebufferBinding || isContextLost())
         return;
 
     m_drawingBuffer->markContentsChanged();
 
     m_layerCleared = false;
     RenderBox* renderBox = canvas()->renderBox();
     if (renderBox && renderBox->hasAcceleratedCompositing()) {
         m_markedCanvasDirty = true;
         canvas()->clearCopiedImage();
         renderBox->contentChanged(CanvasChanged);
     } else {
         if (!m_markedCanvasDirty) {
             m_markedCanvasDirty = true;
             canvas()->didDraw(FloatRect(FloatPoint(0, 0), clampedCanvasSize()));
         }
     }
 }
 
-bool WebGLRenderingContext::clearIfComposited(GLbitfield mask)
+bool WebGLRenderingContextBase::clearIfComposited(GLbitfield mask)
 {
     if (isContextLost())
         return false;
 
     if (!m_drawingBuffer->layerComposited() || m_layerCleared
         || m_requestedAttributes->preserveDrawingBuffer() || (mask && m_framebufferBinding))
         return false;
 
     RefPtr<WebGLContextAttributes> contextAttributes = getContextAttributes();
 
@@ skipping 28 matching lines @@
     m_drawingBuffer->clearFramebuffers(clearMask);
 
     restoreStateAfterClear();
     if (m_framebufferBinding)
         m_context->bindFramebuffer(GL_FRAMEBUFFER, objectOrZero(m_framebufferBinding.get()));
     m_layerCleared = true;
 
     return combinedClear;
 }
 
-void WebGLRenderingContext::restoreStateAfterClear()
+void WebGLRenderingContextBase::restoreStateAfterClear()
 {
     if (isContextLost())
         return;
 
     // Restore the state that the context set.
     if (m_scissorEnabled)
         m_context->enable(GL_SCISSOR_TEST);
     m_context->clearColor(m_clearColor[0], m_clearColor[1],
                           m_clearColor[2], m_clearColor[3]);
     m_context->colorMask(m_colorMask[0], m_colorMask[1],
                          m_colorMask[2], m_colorMask[3]);
     m_context->clearDepth(m_clearDepth);
     m_context->clearStencil(m_clearStencil);
     m_context->stencilMaskSeparate(GL_FRONT, m_stencilMask);
     m_context->depthMask(m_depthMask);
 }
 
-void WebGLRenderingContext::markLayerComposited()
+void WebGLRenderingContextBase::markLayerComposited()
 {
     if (!isContextLost())
         m_drawingBuffer->markLayerComposited();
 }
 
-void WebGLRenderingContext::paintRenderingResultsToCanvas()
+void WebGLRenderingContextBase::paintRenderingResultsToCanvas()
 {
     if (isContextLost()) {
         canvas()->clearPresentationCopy();
         return;
     }
 
     if (canvas()->document().printing())
         canvas()->clearPresentationCopy();
 
     // Until the canvas is written to by the application, the clear that
@@ skipping 18 matching lines @@
         if (canvas()->hasImageBuffer())
             m_drawingBuffer->paintRenderingResultsToCanvas(canvas()->buffer());
     }
 
     if (m_framebufferBinding)
         m_context->bindFramebuffer(GL_FRAMEBUFFER, objectOrZero(m_framebufferBinding.get()));
     else
         m_drawingBuffer->bind();
 }
 
-PassRefPtr<ImageData> WebGLRenderingContext::paintRenderingResultsToImageData()
+PassRefPtr<ImageData> WebGLRenderingContextBase::paintRenderingResultsToImageData()
 {
     if (isContextLost())
         return nullptr;
 
     clearIfComposited();
     m_drawingBuffer->commit();
     int width, height;
     RefPtr<Uint8ClampedArray> imageDataPixels = m_drawingBuffer->paintRenderingResultsToImageData(width, height);
     if (!imageDataPixels)
         return nullptr;
 
     if (m_framebufferBinding)
         m_context->bindFramebuffer(GL_FRAMEBUFFER, objectOrZero(m_framebufferBinding.get()));
     else
         m_drawingBuffer->bind();
 
     return ImageData::create(IntSize(width, height), imageDataPixels);
 }
 
-void WebGLRenderingContext::reshape(int width, int height)
+void WebGLRenderingContextBase::reshape(int width, int height)
 {
     if (isContextLost())
         return;
 
-    // This is an approximation because at WebGLRenderingContext level we don't
+    // This is an approximation because at WebGLRenderingContextBase level we don't
     // know if the underlying FBO uses textures or renderbuffers.
     GLint maxSize = std::min(m_maxTextureSize, m_maxRenderbufferSize);
     // Limit drawing buffer size to 4k to avoid memory exhaustion.
     const int sizeUpperLimit = 4096;
     maxSize = std::min(maxSize, sizeUpperLimit);
     GLint maxWidth = std::min(maxSize, m_maxViewportDims[0]);
     GLint maxHeight = std::min(maxSize, m_maxViewportDims[1]);
     width = clamp(width, 1, maxWidth);
     height = clamp(height, 1, maxHeight);
 
     if (m_needsUpdate) {
         RenderBox* renderBox = canvas()->renderBox();
         if (renderBox && renderBox->hasAcceleratedCompositing())
             renderBox->contentChanged(CanvasChanged);
         m_needsUpdate = false;
     }
 
     // We don't have to mark the canvas as dirty, since the newly created image buffer will also start off
     // clear (and this matches what reshape will do).
     m_drawingBuffer->reset(IntSize(width, height));
     restoreStateAfterClear();
 
     m_context->bindTexture(GL_TEXTURE_2D, objectOrZero(m_textureUnits[m_activeTextureUnit].m_texture2DBinding.get()));
     m_context->bindRenderbuffer(GL_RENDERBUFFER, objectOrZero(m_renderbufferBinding.get()));
     if (m_framebufferBinding)
         m_context->bindFramebuffer(GL_FRAMEBUFFER, objectOrZero(m_framebufferBinding.get()));
 }
 
-int WebGLRenderingContext::drawingBufferWidth() const
+int WebGLRenderingContextBase::drawingBufferWidth() const
 {
     return m_drawingBuffer->size().width();
 }
 
-int WebGLRenderingContext::drawingBufferHeight() const
+int WebGLRenderingContextBase::drawingBufferHeight() const
 {
     return m_drawingBuffer->size().height();
 }
 
-unsigned WebGLRenderingContext::sizeInBytes(GLenum type)
+unsigned WebGLRenderingContextBase::sizeInBytes(GLenum type)
 {
     switch (type) {
     case GL_BYTE:
         return sizeof(GLbyte);
     case GL_UNSIGNED_BYTE:
         return sizeof(GLubyte);
     case GL_SHORT:
         return sizeof(GLshort);
     case GL_UNSIGNED_SHORT:
         return sizeof(GLushort);
     case GL_INT:
         return sizeof(GLint);
     case GL_UNSIGNED_INT:
         return sizeof(GLuint);
     case GL_FLOAT:
         return sizeof(GLfloat);
     }
     ASSERT_NOT_REACHED();
     return 0;
 }
 
-void WebGLRenderingContext::activeTexture(GLenum texture)
+void WebGLRenderingContextBase::activeTexture(GLenum texture)
 {
     if (isContextLost())
         return;
     if (texture - GL_TEXTURE0 >= m_textureUnits.size()) {
         synthesizeGLError(GL_INVALID_ENUM, "activeTexture", "texture unit out of range");
         return;
     }
     m_activeTextureUnit = texture - GL_TEXTURE0;
     m_context->activeTexture(texture);
 
     m_drawingBuffer->setActiveTextureUnit(texture);
 
 }
 
-void WebGLRenderingContext::attachShader(WebGLProgram* program, WebGLShader* shader)
+void WebGLRenderingContextBase::attachShader(WebGLProgram* program, WebGLShader* shader)
 {
     if (isContextLost() || !validateWebGLObject("attachShader", program) || !validateWebGLObject("attachShader", shader))
         return;
     if (!program->attachShader(shader)) {
         synthesizeGLError(GL_INVALID_OPERATION, "attachShader", "shader attachment already has shader");
         return;
     }
     m_context->attachShader(objectOrZero(program), objectOrZero(shader));
     shader->onAttached();
 }
 
-void WebGLRenderingContext::bindAttribLocation(WebGLProgram* program, GLuint index, const String& name)
+void WebGLRenderingContextBase::bindAttribLocation(WebGLProgram* program, GLuint index, const String& name)
 {
     if (isContextLost() || !validateWebGLObject("bindAttribLocation", program))
         return;
     if (!validateLocationLength("bindAttribLocation", name))
         return;
     if (!validateString("bindAttribLocation", name))
         return;
     if (isPrefixReserved(name)) {
         synthesizeGLError(GL_INVALID_OPERATION, "bindAttribLocation", "reserved prefix");
         return;
     }
     if (index >= m_maxVertexAttribs) {
         synthesizeGLError(GL_INVALID_VALUE, "bindAttribLocation", "index out of range");
         return;
     }
     m_context->bindAttribLocation(objectOrZero(program), index, name.utf8().data());
 }
 
-bool WebGLRenderingContext::checkObjectToBeBound(const char* functionName, WebGLObject* object, bool& deleted)
+bool WebGLRenderingContextBase::checkObjectToBeBound(const char* functionName, WebGLObject* object, bool& deleted)
 {
     deleted = false;
     if (isContextLost())
         return false;
     if (object) {
         if (!object->validate(contextGroup(), this)) {
             synthesizeGLError(GL_INVALID_OPERATION, functionName, "object not from this context");
             return false;
         }
         deleted = !object->object();
     }
     return true;
 }
 
-void WebGLRenderingContext::bindBuffer(GLenum target, WebGLBuffer* buffer)
+void WebGLRenderingContextBase::bindBuffer(GLenum target, WebGLBuffer* buffer)
 {
     bool deleted;
     if (!checkObjectToBeBound("bindBuffer", buffer, deleted))
         return;
     if (deleted)
         buffer = 0;
     if (buffer && buffer->getTarget() && buffer->getTarget() != target) {
         synthesizeGLError(GL_INVALID_OPERATION, "bindBuffer", "buffers can not be used with multiple targets");
         return;
     }
     if (target == GL_ARRAY_BUFFER)
         m_boundArrayBuffer = buffer;
     else if (target == GL_ELEMENT_ARRAY_BUFFER)
         m_boundVertexArrayObject->setElementArrayBuffer(buffer);
     else {
         synthesizeGLError(GL_INVALID_ENUM, "bindBuffer", "invalid target");
         return;
     }
 
     m_context->bindBuffer(target, objectOrZero(buffer));
     if (buffer)
         buffer->setTarget(target);
 }
 
-void WebGLRenderingContext::bindFramebuffer(GLenum target, WebGLFramebuffer* buffer)
+void WebGLRenderingContextBase::bindFramebuffer(GLenum target, WebGLFramebuffer* buffer)
 {
     bool deleted;
     if (!checkObjectToBeBound("bindFramebuffer", buffer, deleted))
         return;
     if (deleted)
         buffer = 0;
     if (target != GL_FRAMEBUFFER) {
         synthesizeGLError(GL_INVALID_ENUM, "bindFramebuffer", "invalid target");
         return;
     }
     m_framebufferBinding = buffer;
     m_drawingBuffer->setFramebufferBinding(objectOrZero(m_framebufferBinding.get()));
     if (!m_framebufferBinding) {
         // Instead of binding fb 0, bind the drawing buffer.
         m_drawingBuffer->bind();
     } else
         m_context->bindFramebuffer(target, objectOrZero(buffer));
     if (buffer)
         buffer->setHasEverBeenBound();
     applyStencilTest();
 }
 
-void WebGLRenderingContext::bindRenderbuffer(GLenum target, WebGLRenderbuffer* renderBuffer)
+void WebGLRenderingContextBase::bindRenderbuffer(GLenum target, WebGLRenderbuffer* renderBuffer)
 {
     bool deleted;
     if (!checkObjectToBeBound("bindRenderbuffer", renderBuffer, deleted))
         return;
     if (deleted)
         renderBuffer = 0;
     if (target != GL_RENDERBUFFER) {
         synthesizeGLError(GL_INVALID_ENUM, "bindRenderbuffer", "invalid target");
         return;
     }
     m_renderbufferBinding = renderBuffer;
     m_context->bindRenderbuffer(target, objectOrZero(renderBuffer));
     if (renderBuffer)
         renderBuffer->setHasEverBeenBound();
 }
 
-void WebGLRenderingContext::bindTexture(GLenum target, WebGLTexture* texture)
+void WebGLRenderingContextBase::bindTexture(GLenum target, WebGLTexture* texture)
 {
     bool deleted;
     if (!checkObjectToBeBound("bindTexture", texture, deleted))
         return;
     if (deleted)
         texture = 0;
     if (texture && texture->getTarget() && texture->getTarget() != target) {
         synthesizeGLError(GL_INVALID_OPERATION, "bindTexture", "textures can not be used with multiple targets");
         return;
     }
@@ skipping 28 matching lines @@
     // repeat mode to CLAMP_TO_EDGE for cube map textures, because OpenGL
     // ES 2.0 doesn't expose this flag (a bug in the specification) and
     // otherwise the application has no control over the seams in this
     // dimension. However, it appears that supporting this properly on all
     // platforms is fairly involved (will require a HashMap from texture ID
     // in all ports), and we have not had any complaints, so the logic has
     // been removed.
 
 }
 
-void WebGLRenderingContext::blendColor(GLfloat red, GLfloat green, GLfloat blue, GLfloat alpha)
+void WebGLRenderingContextBase::blendColor(GLfloat red, GLfloat green, GLfloat blue, GLfloat alpha)
 {
     if (isContextLost())
         return;
     m_context->blendColor(red, green, blue, alpha);
 }
 
-void WebGLRenderingContext::blendEquation(GLenum mode)
+void WebGLRenderingContextBase::blendEquation(GLenum mode)
 {
     if (isContextLost() || !validateBlendEquation("blendEquation", mode))
         return;
     m_context->blendEquation(mode);
 }
 
-void WebGLRenderingContext::blendEquationSeparate(GLenum modeRGB, GLenum modeAlpha)
+void WebGLRenderingContextBase::blendEquationSeparate(GLenum modeRGB, GLenum modeAlpha)
 {
     if (isContextLost() || !validateBlendEquation("blendEquationSeparate", modeRGB) || !validateBlendEquation("blendEquationSeparate", modeAlpha))
         return;
     m_context->blendEquationSeparate(modeRGB, modeAlpha);
 }
 
 
-void WebGLRenderingContext::blendFunc(GLenum sfactor, GLenum dfactor)
+void WebGLRenderingContextBase::blendFunc(GLenum sfactor, GLenum dfactor)
 {
     if (isContextLost() || !validateBlendFuncFactors("blendFunc", sfactor, dfactor))
         return;
     m_context->blendFunc(sfactor, dfactor);
 }
 
-void WebGLRenderingContext::blendFuncSeparate(GLenum srcRGB, GLenum dstRGB, GLenum srcAlpha, GLenum dstAlpha)
+void WebGLRenderingContextBase::blendFuncSeparate(GLenum srcRGB, GLenum dstRGB, GLenum srcAlpha, GLenum dstAlpha)
 {
     // Note: Alpha does not have the same restrictions as RGB.
     if (isContextLost() || !validateBlendFuncFactors("blendFuncSeparate", srcRGB, dstRGB))
         return;
     m_context->blendFuncSeparate(srcRGB, dstRGB, srcAlpha, dstAlpha);
 }
 
-void WebGLRenderingContext::bufferData(GLenum target, long long size, GLenum usage)
+void WebGLRenderingContextBase::bufferData(GLenum target, long long size, GLenum usage)
 {
     if (isContextLost())
         return;
     WebGLBuffer* buffer = validateBufferDataParameters("bufferData", target, usage);
     if (!buffer)
         return;
     if (size < 0) {
         synthesizeGLError(GL_INVALID_VALUE, "bufferData", "size < 0");
         return;
     }
     if (!size) {
         synthesizeGLError(GL_INVALID_VALUE, "bufferData", "size == 0");
         return;
     }
 
     m_context->bufferData(target, static_cast<GLsizeiptr>(size), 0, usage);
 }
 
-void WebGLRenderingContext::bufferData(GLenum target, ArrayBuffer* data, GLenum usage)
+void WebGLRenderingContextBase::bufferData(GLenum target, ArrayBuffer* data, GLenum usage)
 {
     if (isContextLost())
         return;
     WebGLBuffer* buffer = validateBufferDataParameters("bufferData", target, usage);
     if (!buffer)
         return;
     if (!data) {
         synthesizeGLError(GL_INVALID_VALUE, "bufferData", "no data");
         return;
     }
     m_context->bufferData(target, data->byteLength(), data->data(), usage);
 }
 
-void WebGLRenderingContext::bufferData(GLenum target, ArrayBufferView* data, GLenum usage)
+void WebGLRenderingContextBase::bufferData(GLenum target, ArrayBufferView* data, GLenum usage)
 {
     if (isContextLost())
         return;
     WebGLBuffer* buffer = validateBufferDataParameters("bufferData", target, usage);
     if (!buffer)
         return;
     if (!data) {
         synthesizeGLError(GL_INVALID_VALUE, "bufferData", "no data");
         return;
     }
 
     m_context->bufferData(target, data->byteLength(), data->baseAddress(), usage);
 }
 
-void WebGLRenderingContext::bufferSubData(GLenum target, long long offset, ArrayBuffer* data)
+void WebGLRenderingContextBase::bufferSubData(GLenum target, long long offset, ArrayBuffer* data)
 {
     if (isContextLost())
         return;
     WebGLBuffer* buffer = validateBufferDataParameters("bufferSubData", target, GL_STATIC_DRAW);
     if (!buffer)
         return;
     if (offset < 0) {
         synthesizeGLError(GL_INVALID_VALUE, "bufferSubData", "offset < 0");
         return;
     }
     if (!data)
         return;
 
     m_context->bufferSubData(target, static_cast<GLintptr>(offset), data->byteLength(), data->data());
 }
 
-void WebGLRenderingContext::bufferSubData(GLenum target, long long offset, ArrayBufferView* data)
+void WebGLRenderingContextBase::bufferSubData(GLenum target, long long offset, ArrayBufferView* data)
 {
     if (isContextLost())
         return;
     WebGLBuffer* buffer = validateBufferDataParameters("bufferSubData", target, GL_STATIC_DRAW);
     if (!buffer)
         return;
     if (offset < 0) {
         synthesizeGLError(GL_INVALID_VALUE, "bufferSubData", "offset < 0");
         return;
     }
     if (!data)
         return;
 
     m_context->bufferSubData(target, static_cast<GLintptr>(offset), data->byteLength(), data->baseAddress());
 }
 
-GLenum WebGLRenderingContext::checkFramebufferStatus(GLenum target)
+GLenum WebGLRenderingContextBase::checkFramebufferStatus(GLenum target)
 {
     if (isContextLost())
         return GL_FRAMEBUFFER_UNSUPPORTED;
     if (target != GL_FRAMEBUFFER) {
         synthesizeGLError(GL_INVALID_ENUM, "checkFramebufferStatus", "invalid target");
         return 0;
     }
     if (!m_framebufferBinding || !m_framebufferBinding->object())
         return GL_FRAMEBUFFER_COMPLETE;
     const char* reason = "framebuffer incomplete";
     GLenum result = m_framebufferBinding->checkStatus(&reason);
     if (result != GL_FRAMEBUFFER_COMPLETE) {
         emitGLWarning("checkFramebufferStatus", reason);
         return result;
     }
     result = m_context->checkFramebufferStatus(target);
     return result;
 }
 
-void WebGLRenderingContext::clear(GLbitfield mask)
+void WebGLRenderingContextBase::clear(GLbitfield mask)
 {
     if (isContextLost())
         return;
     if (mask & ~(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT)) {
         synthesizeGLError(GL_INVALID_VALUE, "clear", "invalid mask");
         return;
     }
     const char* reason = "framebuffer incomplete";
     if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context.get(), &reason)) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, "clear", reason);
         return;
     }
     if (!clearIfComposited(mask))
         m_context->clear(mask);
     markContextChanged();
 }
 
-void WebGLRenderingContext::clearColor(GLfloat r, GLfloat g, GLfloat b, GLfloat a)
+void WebGLRenderingContextBase::clearColor(GLfloat r, GLfloat g, GLfloat b, GLfloat a)
 {
     if (isContextLost())
         return;
     if (std::isnan(r))
         r = 0;
     if (std::isnan(g))
         g = 0;
     if (std::isnan(b))
         b = 0;
     if (std::isnan(a))
         a = 1;
     m_clearColor[0] = r;
     m_clearColor[1] = g;
     m_clearColor[2] = b;
     m_clearColor[3] = a;
     m_context->clearColor(r, g, b, a);
 }
 
-void WebGLRenderingContext::clearDepth(GLfloat depth)
+void WebGLRenderingContextBase::clearDepth(GLfloat depth)
 {
     if (isContextLost())
         return;
     m_clearDepth = depth;
     m_context->clearDepth(depth);
 }
 
-void WebGLRenderingContext::clearStencil(GLint s)
+void WebGLRenderingContextBase::clearStencil(GLint s)
 {
     if (isContextLost())
         return;
     m_clearStencil = s;
     m_context->clearStencil(s);
 }
 
-void WebGLRenderingContext::colorMask(GLboolean red, GLboolean green, GLboolean blue, GLboolean alpha)
+void WebGLRenderingContextBase::colorMask(GLboolean red, GLboolean green, GLboolean blue, GLboolean alpha)
 {
     if (isContextLost())
         return;
     m_colorMask[0] = red;
     m_colorMask[1] = green;
     m_colorMask[2] = blue;
     m_colorMask[3] = alpha;
     m_context->colorMask(red, green, blue, alpha);
 }
 
-void WebGLRenderingContext::compileShader(WebGLShader* shader)
+void WebGLRenderingContextBase::compileShader(WebGLShader* shader)
 {
     if (isContextLost() || !validateWebGLObject("compileShader", shader))
         return;
     m_context->compileShader(objectOrZero(shader));
 }
 
-void WebGLRenderingContext::compressedTexImage2D(GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLint border, ArrayBufferView* data)
+void WebGLRenderingContextBase::compressedTexImage2D(GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLint border, ArrayBufferView* data)
 {
     if (isContextLost())
         return;
     if (!validateTexFuncLevel("compressedTexImage2D", target, level))
         return;
 
     if (!validateCompressedTexFormat(internalformat)) {
         synthesizeGLError(GL_INVALID_ENUM, "compressedTexImage2D", "invalid internalformat");
         return;
     }
@@ skipping 13 matching lines @@
         if (level && WebGLTexture::isNPOT(width, height)) {
             synthesizeGLError(GL_INVALID_VALUE, "compressedTexImage2D", "level > 0 not power of 2");
             return;
         }
     }
     m_context->compressedTexImage2D(target, level, internalformat, width, height,
                                               border, data->byteLength(), data->baseAddress());
     tex->setLevelInfo(target, level, internalformat, width, height, GL_UNSIGNED_BYTE);
 }
 
-void WebGLRenderingContext::compressedTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, ArrayBufferView* data)
+void WebGLRenderingContextBase::compressedTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, ArrayBufferView* data)
 {
     if (isContextLost())
         return;
     if (!validateTexFuncLevel("compressedTexSubImage2D", target, level))
         return;
     if (!validateCompressedTexFormat(format)) {
         synthesizeGLError(GL_INVALID_ENUM, "compressedTexSubImage2D", "invalid format");
         return;
     }
     if (!validateCompressedTexFuncData("compressedTexSubImage2D", width, height, format, data))
         return;
 
     WebGLTexture* tex = validateTextureBinding("compressedTexSubImage2D", target, true);
     if (!tex)
         return;
 
     if (format != tex->getInternalFormat(target, level)) {
         synthesizeGLError(GL_INVALID_OPERATION, "compressedTexSubImage2D", "format does not match texture format");
         return;
     }
 
     if (!validateCompressedTexSubDimensions("compressedTexSubImage2D", target, level, xoffset, yoffset, width, height, format, tex))
         return;
 
     m_context->compressedTexSubImage2D(target, level, xoffset, yoffset,
                                                  width, height, format, data->byteLength(), data->baseAddress());
 }
 
-bool WebGLRenderingContext::validateSettableTexFormat(const char* functionName, GLenum format)
+bool WebGLRenderingContextBase::validateSettableTexFormat(const char* functionName, GLenum format)
 {
     if (WebGLImageConversion::getClearBitsByFormat(format) & (GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT)) {
         synthesizeGLError(GL_INVALID_OPERATION, functionName, "format can not be set, only rendered to");
         return false;
     }
     return true;
 }
 
-void WebGLRenderingContext::copyTexImage2D(GLenum target, GLint level, GLenum internalformat, GLint x, GLint y, GLsizei width, GLsizei height, GLint border)
+void WebGLRenderingContextBase::copyTexImage2D(GLenum target, GLint level, GLenum internalformat, GLint x, GLint y, GLsizei width, GLsizei height, GLint border)
 {
     if (isContextLost())
         return;
     if (!validateTexFuncParameters("copyTexImage2D", NotTexSubImage2D, target, level, internalformat, width, height, border, internalformat, GL_UNSIGNED_BYTE))
         return;
     if (!validateSettableTexFormat("copyTexImage2D", internalformat))
         return;
     WebGLTexture* tex = validateTextureBinding("copyTexImage2D", target, true);
     if (!tex)
         return;
@@ skipping 10 matching lines @@
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, "copyTexImage2D", reason);
         return;
     }
     clearIfComposited();
     ScopedDrawingBufferBinder binder(m_drawingBuffer.get(), m_framebufferBinding.get());
     m_context->copyTexImage2D(target, level, internalformat, x, y, width, height, border);
     // FIXME: if the framebuffer is not complete, none of the below should be executed.
     tex->setLevelInfo(target, level, internalformat, width, height, GL_UNSIGNED_BYTE);
 }
 
-void WebGLRenderingContext::copyTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLint x, GLint y, GLsizei width, GLsizei height)
+void WebGLRenderingContextBase::copyTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLint x, GLint y, GLsizei width, GLsizei height)
 {
     if (isContextLost())
         return;
     if (!validateTexFuncLevel("copyTexSubImage2D", target, level))
         return;
     WebGLTexture* tex = validateTextureBinding("copyTexSubImage2D", target, true);
     if (!tex)
         return;
     if (!validateSize("copyTexSubImage2D", xoffset, yoffset) || !validateSize("copyTexSubImage2D", width, height))
         return;
@@ skipping 20 matching lines @@
     const char* reason = "framebuffer incomplete";
     if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context.get(), &reason)) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, "copyTexSubImage2D", reason);
         return;
     }
     clearIfComposited();
     ScopedDrawingBufferBinder binder(m_drawingBuffer.get(), m_framebufferBinding.get());
     m_context->copyTexSubImage2D(target, level, xoffset, yoffset, x, y, width, height);
 }
 
-PassRefPtr<WebGLBuffer> WebGLRenderingContext::createBuffer()
+PassRefPtr<WebGLBuffer> WebGLRenderingContextBase::createBuffer()
 {
     if (isContextLost())
         return nullptr;
     RefPtr<WebGLBuffer> o = WebGLBuffer::create(this);
     addSharedObject(o.get());
     return o;
 }
 
-PassRefPtr<WebGLFramebuffer> WebGLRenderingContext::createFramebuffer()
+PassRefPtr<WebGLFramebuffer> WebGLRenderingContextBase::createFramebuffer()
 {
     if (isContextLost())
         return nullptr;
     RefPtr<WebGLFramebuffer> o = WebGLFramebuffer::create(this);
     addContextObject(o.get());
     return o;
 }
 
-PassRefPtr<WebGLTexture> WebGLRenderingContext::createTexture()
+PassRefPtr<WebGLTexture> WebGLRenderingContextBase::createTexture()
 {
     if (isContextLost())
         return nullptr;
     RefPtr<WebGLTexture> o = WebGLTexture::create(this);
     addSharedObject(o.get());
     return o;
 }
 
-PassRefPtr<WebGLProgram> WebGLRenderingContext::createProgram()
+PassRefPtr<WebGLProgram> WebGLRenderingContextBase::createProgram()
 {
     if (isContextLost())
         return nullptr;
     RefPtr<WebGLProgram> o = WebGLProgram::create(this);
     addSharedObject(o.get());
     return o;
 }
 
-PassRefPtr<WebGLRenderbuffer> WebGLRenderingContext::createRenderbuffer()
+PassRefPtr<WebGLRenderbuffer> WebGLRenderingContextBase::createRenderbuffer()
 {
     if (isContextLost())
         return nullptr;
     RefPtr<WebGLRenderbuffer> o = WebGLRenderbuffer::create(this);
     addSharedObject(o.get());
     return o;
 }
 
-WebGLRenderbuffer* WebGLRenderingContext::ensureEmulatedStencilBuffer(GLenum target, WebGLRenderbuffer* renderbuffer)
+WebGLRenderbuffer* WebGLRenderingContextBase::ensureEmulatedStencilBuffer(GLenum target, WebGLRenderbuffer* renderbuffer)
 {
     if (isContextLost())
         return 0;
     if (!renderbuffer->emulatedStencilBuffer()) {
         renderbuffer->setEmulatedStencilBuffer(createRenderbuffer());
         m_context->bindRenderbuffer(target, objectOrZero(renderbuffer->emulatedStencilBuffer()));
         m_context->bindRenderbuffer(target, objectOrZero(m_renderbufferBinding.get()));
     }
     return renderbuffer->emulatedStencilBuffer();
 }
 
-PassRefPtr<WebGLShader> WebGLRenderingContext::createShader(GLenum type)
+PassRefPtr<WebGLShader> WebGLRenderingContextBase::createShader(GLenum type)
 {
     if (isContextLost())
         return nullptr;
     if (type != GL_VERTEX_SHADER && type != GL_FRAGMENT_SHADER) {
         synthesizeGLError(GL_INVALID_ENUM, "createShader", "invalid shader type");
         return nullptr;
     }
 
     RefPtr<WebGLShader> o = WebGLShader::create(this, type);
     addSharedObject(o.get());
     return o;
 }
 
-void WebGLRenderingContext::cullFace(GLenum mode)
+void WebGLRenderingContextBase::cullFace(GLenum mode)
 {
     if (isContextLost())
         return;
     switch (mode) {
     case GL_FRONT_AND_BACK:
     case GL_FRONT:
     case GL_BACK:
         break;
     default:
         synthesizeGLError(GL_INVALID_ENUM, "cullFace", "invalid mode");
         return;
     }
     m_context->cullFace(mode);
 }
 
-bool WebGLRenderingContext::deleteObject(WebGLObject* object)
+bool WebGLRenderingContextBase::deleteObject(WebGLObject* object)
 {
     if (isContextLost() || !object)
         return false;
     if (!object->validate(contextGroup(), this)) {
         synthesizeGLError(GL_INVALID_OPERATION, "delete", "object does not belong to this context");
         return false;
     }
     if (object->object()) {
         // We need to pass in context here because we want
         // things in this context unbound.
         object->deleteObject(m_context.get());
     }
     return true;
 }
 
-void WebGLRenderingContext::deleteBuffer(WebGLBuffer* buffer)
+void WebGLRenderingContextBase::deleteBuffer(WebGLBuffer* buffer)
 {
     if (!deleteObject(buffer))
         return;
     if (m_boundArrayBuffer == buffer)
         m_boundArrayBuffer = nullptr;
 
     m_boundVertexArrayObject->unbindBuffer(buffer);
 }
 
-void WebGLRenderingContext::deleteFramebuffer(WebGLFramebuffer* framebuffer)
+void WebGLRenderingContextBase::deleteFramebuffer(WebGLFramebuffer* framebuffer)
 {
     if (!deleteObject(framebuffer))
         return;
     if (framebuffer == m_framebufferBinding) {
         m_framebufferBinding = nullptr;
         m_drawingBuffer->setFramebufferBinding(0);
         // Have to call bindFramebuffer here to bind back to internal fbo.
         m_drawingBuffer->bind();
     }
 }
 
-void WebGLRenderingContext::deleteProgram(WebGLProgram* program)
+void WebGLRenderingContextBase::deleteProgram(WebGLProgram* program)
 {
     deleteObject(program);
     // We don't reset m_currentProgram to 0 here because the deletion of the
     // current program is delayed.
 }
 
-void WebGLRenderingContext::deleteRenderbuffer(WebGLRenderbuffer* renderbuffer)
+void WebGLRenderingContextBase::deleteRenderbuffer(WebGLRenderbuffer* renderbuffer)
 {
     if (!deleteObject(renderbuffer))
         return;
     if (renderbuffer == m_renderbufferBinding)
         m_renderbufferBinding = nullptr;
     if (m_framebufferBinding)
         m_framebufferBinding->removeAttachmentFromBoundFramebuffer(renderbuffer);
 }
 
-void WebGLRenderingContext::deleteShader(WebGLShader* shader)
+void WebGLRenderingContextBase::deleteShader(WebGLShader* shader)
 {
     deleteObject(shader);
 }
 
-void WebGLRenderingContext::deleteTexture(WebGLTexture* texture)
+void WebGLRenderingContextBase::deleteTexture(WebGLTexture* texture)
 {
     if (!deleteObject(texture))
         return;
 
     int maxBoundTextureIndex = -1;
     for (size_t i = 0; i < m_onePlusMaxNonDefaultTextureUnit; ++i) {
         if (texture == m_textureUnits[i].m_texture2DBinding) {
             m_textureUnits[i].m_texture2DBinding = nullptr;
             maxBoundTextureIndex = i;
             if (!i)
                 m_drawingBuffer->setTexture2DBinding(0);
         }
         if (texture == m_textureUnits[i].m_textureCubeMapBinding) {
             m_textureUnits[i].m_textureCubeMapBinding = nullptr;
             maxBoundTextureIndex = i;
         }
     }
     if (m_framebufferBinding)
         m_framebufferBinding->removeAttachmentFromBoundFramebuffer(texture);
 
     // If the deleted was bound to the the current maximum index, trace backwards to find the new max texture index
     if (m_onePlusMaxNonDefaultTextureUnit == static_cast<unsigned long>(maxBoundTextureIndex + 1)) {
         findNewMaxNonDefaultTextureUnit();
     }
 }
 
-void WebGLRenderingContext::depthFunc(GLenum func)
+void WebGLRenderingContextBase::depthFunc(GLenum func)
 {
     if (isContextLost())
         return;
     if (!validateStencilOrDepthFunc("depthFunc", func))
         return;
     m_context->depthFunc(func);
 }
 
-void WebGLRenderingContext::depthMask(GLboolean flag)
+void WebGLRenderingContextBase::depthMask(GLboolean flag)
 {
     if (isContextLost())
         return;
     m_depthMask = flag;
     m_context->depthMask(flag);
 }
 
-void WebGLRenderingContext::depthRange(GLfloat zNear, GLfloat zFar)
+void WebGLRenderingContextBase::depthRange(GLfloat zNear, GLfloat zFar)
 {
     if (isContextLost())
         return;
     if (zNear > zFar) {
         synthesizeGLError(GL_INVALID_OPERATION, "depthRange", "zNear > zFar");
         return;
     }
     m_context->depthRange(zNear, zFar);
 }
 
-void WebGLRenderingContext::detachShader(WebGLProgram* program, WebGLShader* shader)
+void WebGLRenderingContextBase::detachShader(WebGLProgram* program, WebGLShader* shader)
 {
     if (isContextLost() || !validateWebGLObject("detachShader", program) || !validateWebGLObject("detachShader", shader))
         return;
     if (!program->detachShader(shader)) {
         synthesizeGLError(GL_INVALID_OPERATION, "detachShader", "shader not attached");
         return;
     }
     m_context->detachShader(objectOrZero(program), objectOrZero(shader));
     shader->onDetached(m_context.get());
 }
 
-void WebGLRenderingContext::disable(GLenum cap)
+void WebGLRenderingContextBase::disable(GLenum cap)
 {
     if (isContextLost() || !validateCapability("disable", cap))
         return;
     if (cap == GL_STENCIL_TEST) {
         m_stencilEnabled = false;
         applyStencilTest();
         return;
     }
     if (cap == GL_SCISSOR_TEST) {
         m_scissorEnabled = false;
         m_drawingBuffer->setScissorEnabled(m_scissorEnabled);
     }
     m_context->disable(cap);
 }
 
-void WebGLRenderingContext::disableVertexAttribArray(GLuint index)
+void WebGLRenderingContextBase::disableVertexAttribArray(GLuint index)
 {
     if (isContextLost())
         return;
     if (index >= m_maxVertexAttribs) {
         synthesizeGLError(GL_INVALID_VALUE, "disableVertexAttribArray", "index out of range");
         return;
     }
 
     WebGLVertexArrayObjectOES::VertexAttribState& state = m_boundVertexArrayObject->getVertexAttribState(index);
     state.enabled = false;
 
     // If the disabled index is the current maximum, trace backwards to find the new max enabled attrib index
     if (m_onePlusMaxEnabledAttribIndex == index + 1) {
         findNewMaxEnabledAttribIndex();
     }
 
     m_context->disableVertexAttribArray(index);
 }
 
-bool WebGLRenderingContext::validateRenderingState(const char* functionName)
+bool WebGLRenderingContextBase::validateRenderingState(const char* functionName)
 {
     if (!m_currentProgram) {
         synthesizeGLError(GL_INVALID_OPERATION, functionName, "no valid shader program in use");
         return false;
     }
 
     // Look in each enabled vertex attrib and check if they've been bound to a buffer.
     for (unsigned i = 0; i < m_onePlusMaxEnabledAttribIndex; ++i) {
         const WebGLVertexArrayObjectOES::VertexAttribState& state = m_boundVertexArrayObject->getVertexAttribState(i);
         if (state.enabled
             && (!state.bufferBinding || !state.bufferBinding->object())) {
             synthesizeGLError(GL_INVALID_OPERATION, functionName, String::format("attribute %d is enabled but has no buffer bound", i).utf8().data());
             return false;
         }
     }
 
     return true;
 }
 
-bool WebGLRenderingContext::validateWebGLObject(const char* functionName, WebGLObject* object)
+bool WebGLRenderingContextBase::validateWebGLObject(const char* functionName, WebGLObject* object)
 {
     if (!object || !object->object()) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "no object or object deleted");
         return false;
     }
     if (!object->validate(contextGroup(), this)) {
         synthesizeGLError(GL_INVALID_OPERATION, functionName, "object does not belong to this context");
         return false;
     }
     return true;
 }
 
-void WebGLRenderingContext::drawArrays(GLenum mode, GLint first, GLsizei count)
+void WebGLRenderingContextBase::drawArrays(GLenum mode, GLint first, GLsizei count)
 {
     if (!validateDrawArrays("drawArrays", mode, first, count))
         return;
 
     clearIfComposited();
 
     handleTextureCompleteness("drawArrays", true);
     m_context->drawArrays(mode, first, count);
     handleTextureCompleteness("drawArrays", false);
     markContextChanged();
 }
 
-void WebGLRenderingContext::drawElements(GLenum mode, GLsizei count, GLenum type, long long offset)
+void WebGLRenderingContextBase::drawElements(GLenum mode, GLsizei count, GLenum type, long long offset)
 {
     if (!validateDrawElements("drawElements", mode, count, type, offset))
         return;
 
     clearIfComposited();
 
     handleTextureCompleteness("drawElements", true);
     m_context->drawElements(mode, count, type, static_cast<GLintptr>(offset));
     handleTextureCompleteness("drawElements", false);
     markContextChanged();
 }
 
-void WebGLRenderingContext::drawArraysInstancedANGLE(GLenum mode, GLint first, GLsizei count, GLsizei primcount)
+void WebGLRenderingContextBase::drawArraysInstancedANGLE(GLenum mode, GLint first, GLsizei count, GLsizei primcount)
 {
     if (!validateDrawArrays("drawArraysInstancedANGLE", mode, first, count))
         return;
 
     if (!validateDrawInstanced("drawArraysInstancedANGLE", primcount))
         return;
 
     clearIfComposited();
 
     handleTextureCompleteness("drawArraysInstancedANGLE", true);
     m_context->drawArraysInstancedANGLE(mode, first, count, primcount);
     handleTextureCompleteness("drawArraysInstancedANGLE", false);
     markContextChanged();
 }
 
-void WebGLRenderingContext::drawElementsInstancedANGLE(GLenum mode, GLsizei count, GLenum type, GLintptr offset, GLsizei primcount)
+void WebGLRenderingContextBase::drawElementsInstancedANGLE(GLenum mode, GLsizei count, GLenum type, GLintptr offset, GLsizei primcount)
 {
     if (!validateDrawElements("drawElementsInstancedANGLE", mode, count, type, offset))
         return;
 
     if (!validateDrawInstanced("drawElementsInstancedANGLE", primcount))
         return;
 
     clearIfComposited();
 
     handleTextureCompleteness("drawElementsInstancedANGLE", true);
     m_context->drawElementsInstancedANGLE(mode, count, type, static_cast<GLintptr>(offset), primcount);
     handleTextureCompleteness("drawElementsInstancedANGLE", false);
     markContextChanged();
 }
 
-void WebGLRenderingContext::enable(GLenum cap)
+void WebGLRenderingContextBase::enable(GLenum cap)
 {
     if (isContextLost() || !validateCapability("enable", cap))
         return;
     if (cap == GL_STENCIL_TEST) {
         m_stencilEnabled = true;
         applyStencilTest();
         return;
     }
     if (cap == GL_SCISSOR_TEST) {
         m_scissorEnabled = true;
         m_drawingBuffer->setScissorEnabled(m_scissorEnabled);
     }
     m_context->enable(cap);
 }
 
-void WebGLRenderingContext::enableVertexAttribArray(GLuint index)
+void WebGLRenderingContextBase::enableVertexAttribArray(GLuint index)
 {
     if (isContextLost())
         return;
     if (index >= m_maxVertexAttribs) {
         synthesizeGLError(GL_INVALID_VALUE, "enableVertexAttribArray", "index out of range");
         return;
     }
 
     WebGLVertexArrayObjectOES::VertexAttribState& state = m_boundVertexArrayObject->getVertexAttribState(index);
     state.enabled = true;
 
     m_onePlusMaxEnabledAttribIndex = max(index + 1, m_onePlusMaxEnabledAttribIndex);
 
     m_context->enableVertexAttribArray(index);
 }
 
-void WebGLRenderingContext::finish()
+void WebGLRenderingContextBase::finish()
 {
     if (isContextLost())
         return;
     m_context->flush(); // Intentionally a flush, not a finish.
 }
 
-void WebGLRenderingContext::flush()
+void WebGLRenderingContextBase::flush()
 {
     if (isContextLost())
         return;
     m_context->flush();
 }
 
-void WebGLRenderingContext::framebufferRenderbuffer(GLenum target, GLenum attachment, GLenum renderbuffertarget, WebGLRenderbuffer* buffer)
+void WebGLRenderingContextBase::framebufferRenderbuffer(GLenum target, GLenum attachment, GLenum renderbuffertarget, WebGLRenderbuffer* buffer)
 {
     if (isContextLost() || !validateFramebufferFuncParameters("framebufferRenderbuffer", target, attachment))
         return;
     if (renderbuffertarget != GL_RENDERBUFFER) {
         synthesizeGLError(GL_INVALID_ENUM, "framebufferRenderbuffer", "invalid target");
         return;
     }
     if (buffer && !buffer->validate(contextGroup(), this)) {
         synthesizeGLError(GL_INVALID_OPERATION, "framebufferRenderbuffer", "no buffer or buffer not from this context");
         return;
@@ skipping 21 matching lines @@
             m_context->framebufferRenderbuffer(target, GL_STENCIL_ATTACHMENT, renderbuffertarget, objectOrZero(emulatedStencilBuffer));
         }
         break;
     default:
         m_context->framebufferRenderbuffer(target, attachment, renderbuffertarget, bufferObject);
     }
     m_framebufferBinding->setAttachmentForBoundFramebuffer(attachment, buffer);
     applyStencilTest();
 }
 
-void WebGLRenderingContext::framebufferTexture2D(GLenum target, GLenum attachment, GLenum textarget, WebGLTexture* texture, GLint level)
+void WebGLRenderingContextBase::framebufferTexture2D(GLenum target, GLenum attachment, GLenum textarget, WebGLTexture* texture, GLint level)
 {
     if (isContextLost() || !validateFramebufferFuncParameters("framebufferTexture2D", target, attachment))
         return;
     if (level) {
         synthesizeGLError(GL_INVALID_VALUE, "framebufferTexture2D", "level not 0");
         return;
     }
     if (texture && !texture->validate(contextGroup(), this)) {
         synthesizeGLError(GL_INVALID_OPERATION, "framebufferTexture2D", "no texture or texture not from this context");
         return;
@@ skipping 17 matching lines @@
     case GL_STENCIL_ATTACHMENT:
         m_context->framebufferTexture2D(target, attachment, textarget, textureObject, level);
         break;
     default:
         m_context->framebufferTexture2D(target, attachment, textarget, textureObject, level);
     }
     m_framebufferBinding->setAttachmentForBoundFramebuffer(attachment, textarget, texture, level);
     applyStencilTest();
 }
 
-void WebGLRenderingContext::frontFace(GLenum mode)
+void WebGLRenderingContextBase::frontFace(GLenum mode)
 {
     if (isContextLost())
         return;
     switch (mode) {
     case GL_CW:
     case GL_CCW:
         break;
     default:
         synthesizeGLError(GL_INVALID_ENUM, "frontFace", "invalid mode");
         return;
     }
     m_context->frontFace(mode);
 }
 
-void WebGLRenderingContext::generateMipmap(GLenum target)
+void WebGLRenderingContextBase::generateMipmap(GLenum target)
 {
     if (isContextLost())
         return;
     WebGLTexture* tex = validateTextureBinding("generateMipmap", target, false);
     if (!tex)
         return;
     if (!tex->canGenerateMipmaps()) {
         synthesizeGLError(GL_INVALID_OPERATION, "generateMipmap", "level 0 not power of 2 or not all the same size");
         return;
     }
@@ skipping 10 matching lines @@
     }
 #endif
     m_context->generateMipmap(target);
 #if OS(MACOSX)
     if (needToResetMinFilter)
         m_context->texParameteri(target, GL_TEXTURE_MIN_FILTER, tex->getMinFilter());
 #endif
     tex->generateMipmapLevelInfo();
 }
 
-PassRefPtr<WebGLActiveInfo> WebGLRenderingContext::getActiveAttrib(WebGLProgram* program, GLuint index)
+PassRefPtr<WebGLActiveInfo> WebGLRenderingContextBase::getActiveAttrib(WebGLProgram* program, GLuint index)
 {
     if (isContextLost() || !validateWebGLObject("getActiveAttrib", program))
         return nullptr;
     blink::WebGraphicsContext3D::ActiveInfo info;
     if (!m_context->getActiveAttrib(objectOrZero(program), index, info))
         return nullptr;
     return WebGLActiveInfo::create(info.name, info.type, info.size);
 }
 
-PassRefPtr<WebGLActiveInfo> WebGLRenderingContext::getActiveUniform(WebGLProgram* program, GLuint index)
+PassRefPtr<WebGLActiveInfo> WebGLRenderingContextBase::getActiveUniform(WebGLProgram* program, GLuint index)
 {
     if (isContextLost() || !validateWebGLObject("getActiveUniform", program))
         return nullptr;
     blink::WebGraphicsContext3D::ActiveInfo info;
     if (!m_context->getActiveUniform(objectOrZero(program), index, info))
         return nullptr;
     return WebGLActiveInfo::create(info.name, info.type, info.size);
 }
 
-bool WebGLRenderingContext::getAttachedShaders(WebGLProgram* program, Vector<RefPtr<WebGLShader> >& shaderObjects)
+bool WebGLRenderingContextBase::getAttachedShaders(WebGLProgram* program, Vector<RefPtr<WebGLShader> >& shaderObjects)
 {
     shaderObjects.clear();
     if (isContextLost() || !validateWebGLObject("getAttachedShaders", program))
         return false;
 
     const GLenum shaderType[] = {
         GL_VERTEX_SHADER,
         GL_FRAGMENT_SHADER
     };
     for (unsigned i = 0; i < sizeof(shaderType) / sizeof(GLenum); ++i) {
         WebGLShader* shader = program->getAttachedShader(shaderType[i]);
         if (shader)
             shaderObjects.append(shader);
     }
     return true;
 }
 
-GLint WebGLRenderingContext::getAttribLocation(WebGLProgram* program, const String& name)
+GLint WebGLRenderingContextBase::getAttribLocation(WebGLProgram* program, const String& name)
 {
     if (isContextLost() || !validateWebGLObject("getAttribLocation", program))
         return -1;
     if (!validateLocationLength("getAttribLocation", name))
         return -1;
     if (!validateString("getAttribLocation", name))
         return -1;
     if (isPrefixReserved(name))
         return -1;
     if (!program->linkStatus()) {
         synthesizeGLError(GL_INVALID_OPERATION, "getAttribLocation", "program not linked");
         return 0;
     }
     return m_context->getAttribLocation(objectOrZero(program), name.utf8().data());
 }
 
-WebGLGetInfo WebGLRenderingContext::getBufferParameter(GLenum target, GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getBufferParameter(GLenum target, GLenum pname)
 {
     if (isContextLost())
         return WebGLGetInfo();
     if (target != GL_ARRAY_BUFFER && target != GL_ELEMENT_ARRAY_BUFFER) {
         synthesizeGLError(GL_INVALID_ENUM, "getBufferParameter", "invalid target");
         return WebGLGetInfo();
     }
 
     if (pname != GL_BUFFER_SIZE && pname != GL_BUFFER_USAGE) {
         synthesizeGLError(GL_INVALID_ENUM, "getBufferParameter", "invalid parameter name");
         return WebGLGetInfo();
     }
 
     GLint value = 0;
     m_context->getBufferParameteriv(target, pname, &value);
     if (pname == GL_BUFFER_SIZE)
         return WebGLGetInfo(value);
     return WebGLGetInfo(static_cast<unsigned>(value));
 }
 
-PassRefPtr<WebGLContextAttributes> WebGLRenderingContext::getContextAttributes()
+PassRefPtr<WebGLContextAttributes> WebGLRenderingContextBase::getContextAttributes()
 {
     if (isContextLost())
         return nullptr;
     // We always need to return a new WebGLContextAttributes object to
     // prevent the user from mutating any cached version.
     blink::WebGraphicsContext3D::Attributes attrs = m_context->getContextAttributes();
     RefPtr<WebGLContextAttributes> attributes = m_requestedAttributes->clone();
     // Some requested attributes may not be honored, so we need to query the underlying
     // context/drawing buffer and adjust accordingly.
     if (m_requestedAttributes->depth() && !attrs.depth)
         attributes->setDepth(false);
     if (m_requestedAttributes->stencil() && !attrs.stencil)
         attributes->setStencil(false);
     attributes->setAntialias(m_drawingBuffer->multisample());
     return attributes.release();
 }
 
-GLenum WebGLRenderingContext::getError()
+GLenum WebGLRenderingContextBase::getError()
 {
     if (m_lostContextErrors.size()) {
         GLenum err = m_lostContextErrors.first();
         m_lostContextErrors.remove(0);
         return err;
     }
 
     if (isContextLost())
         return GL_NO_ERROR;
 
     return m_context->getError();
 }
 
-bool WebGLRenderingContext::ExtensionTracker::matchesNameWithPrefixes(const String& name) const
+bool WebGLRenderingContextBase::ExtensionTracker::matchesNameWithPrefixes(const String& name) const
 {
     static const char* const unprefixed[] = { "", 0, };
 
     const char* const* prefixes = m_prefixes ? m_prefixes : unprefixed;
     for (; *prefixes; ++prefixes) {
         String prefixedName = String(*prefixes) + extensionName();
         if (equalIgnoringCase(prefixedName, name)) {
             return true;
         }
     }
     return false;
 }
 
-PassRefPtr<WebGLExtension> WebGLRenderingContext::getExtension(const String& name)
+PassRefPtr<WebGLExtension> WebGLRenderingContextBase::getExtension(const String& name)
 {
     if (isContextLost())
         return nullptr;
 
     for (size_t i = 0; i < m_extensions.size(); ++i) {
         ExtensionTracker* tracker = m_extensions[i];
         if (tracker->matchesNameWithPrefixes(name)) {
             if (tracker->webglDebugRendererInfo() && !allowWebGLDebugRendererInfo())
                 return nullptr;
             if (tracker->privileged() && !allowPrivilegedExtensions())
                 return nullptr;
             if (tracker->draft() && !RuntimeEnabledFeatures::webGLDraftExtensionsEnabled())
                 return nullptr;
             if (!tracker->supported(this))
                 return nullptr;
-            return tracker->getExtension(this);
+
+            RefPtr<WebGLExtension> extension = tracker->getExtension(this);
+            if (extension)
+                m_extensionEnabled[extension->name()] = true;
+            return extension.release();
         }
     }
 
     return nullptr;
 }
 
-WebGLGetInfo WebGLRenderingContext::getFramebufferAttachmentParameter(GLenum target, GLenum attachment, GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getFramebufferAttachmentParameter(GLenum target, GLenum attachment, GLenum pname)
 {
     if (isContextLost() || !validateFramebufferFuncParameters("getFramebufferAttachmentParameter", target, attachment))
         return WebGLGetInfo();
 
     if (!m_framebufferBinding || !m_framebufferBinding->object()) {
         synthesizeGLError(GL_INVALID_OPERATION, "getFramebufferAttachmentParameter", "no framebuffer bound");
         return WebGLGetInfo();
     }
 
     WebGLSharedObject* object = m_framebufferBinding->getAttachmentObject(attachment);
@@ skipping 30 matching lines @@
             return WebGLGetInfo(GL_RENDERBUFFER);
         case GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME:
             return WebGLGetInfo(PassRefPtr<WebGLRenderbuffer>(static_cast<WebGLRenderbuffer*>(object)));
         default:
             synthesizeGLError(GL_INVALID_ENUM, "getFramebufferAttachmentParameter", "invalid parameter name for renderbuffer attachment");
             return WebGLGetInfo();
         }
     }
 }
 
-WebGLGetInfo WebGLRenderingContext::getParameter(GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getParameter(GLenum pname)
 {
     if (isContextLost())
         return WebGLGetInfo();
     const int intZero = 0;
     switch (pname) {
     case GL_ACTIVE_TEXTURE:
         return getUnsignedIntParameter(pname);
     case GL_ALIASED_LINE_WIDTH_RANGE:
         return getWebGLFloatArrayParameter(pname);
     case GL_ALIASED_POINT_SIZE_RANGE:
@@ skipping 163 matching lines @@
         return WebGLGetInfo(m_unpackPremultiplyAlpha);
     case GC3D_UNPACK_COLORSPACE_CONVERSION_WEBGL:
         return WebGLGetInfo(m_unpackColorspaceConversion);
     case GL_VENDOR:
         return WebGLGetInfo(String("WebKit"));
     case GL_VERSION:
         return WebGLGetInfo("WebGL 1.0 (" + String(m_context->getString(GL_VERSION)) + ")");
     case GL_VIEWPORT:
         return getWebGLIntArrayParameter(pname);
     case GL_FRAGMENT_SHADER_DERIVATIVE_HINT_OES: // OES_standard_derivatives
-        if (m_oesStandardDerivatives)
+        if (extensionEnabled(OESStandardDerivativesName))
             return getUnsignedIntParameter(GL_FRAGMENT_SHADER_DERIVATIVE_HINT_OES);
         synthesizeGLError(GL_INVALID_ENUM, "getParameter", "invalid parameter name, OES_standard_derivatives not enabled");
         return WebGLGetInfo();
     case WebGLDebugRendererInfo::UNMASKED_RENDERER_WEBGL:
-        if (m_webglDebugRendererInfo)
+        if (extensionEnabled(WebGLDebugRendererInfoName))
             return WebGLGetInfo(m_context->getString(GL_RENDERER));
         synthesizeGLError(GL_INVALID_ENUM, "getParameter", "invalid parameter name, WEBGL_debug_renderer_info not enabled");
         return WebGLGetInfo();
     case WebGLDebugRendererInfo::UNMASKED_VENDOR_WEBGL:
-        if (m_webglDebugRendererInfo)
+        if (extensionEnabled(WebGLDebugRendererInfoName))
             return WebGLGetInfo(m_context->getString(GL_VENDOR));
         synthesizeGLError(GL_INVALID_ENUM, "getParameter", "invalid parameter name, WEBGL_debug_renderer_info not enabled");
         return WebGLGetInfo();
     case GL_VERTEX_ARRAY_BINDING_OES: // OES_vertex_array_object
-        if (m_oesVertexArrayObject) {
+        if (extensionEnabled(OESVertexArrayObjectName)) {
             if (!m_boundVertexArrayObject->isDefaultObject())
                 return WebGLGetInfo(PassRefPtr<WebGLVertexArrayObjectOES>(m_boundVertexArrayObject));
             return WebGLGetInfo();
         }
         synthesizeGLError(GL_INVALID_ENUM, "getParameter", "invalid parameter name, OES_vertex_array_object not enabled");
         return WebGLGetInfo();
     case GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT: // EXT_texture_filter_anisotropic
-        if (m_extTextureFilterAnisotropic)
+        if (extensionEnabled(EXTTextureFilterAnisotropicName))
             return getUnsignedIntParameter(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT);
         synthesizeGLError(GL_INVALID_ENUM, "getParameter", "invalid parameter name, EXT_texture_filter_anisotropic not enabled");
         return WebGLGetInfo();
     case GL_MAX_COLOR_ATTACHMENTS_EXT: // EXT_draw_buffers BEGIN
-        if (m_webglDrawBuffers)
+        if (extensionEnabled(WebGLDrawBuffersName))
             return WebGLGetInfo(maxColorAttachments());
         synthesizeGLError(GL_INVALID_ENUM, "getParameter", "invalid parameter name, WEBGL_draw_buffers not enabled");
         return WebGLGetInfo();
     case GL_MAX_DRAW_BUFFERS_EXT:
-        if (m_webglDrawBuffers)
+        if (extensionEnabled(WebGLDrawBuffersName))
             return WebGLGetInfo(maxDrawBuffers());
         synthesizeGLError(GL_INVALID_ENUM, "getParameter", "invalid parameter name, WEBGL_draw_buffers not enabled");
         return WebGLGetInfo();
     default:
-        if (m_webglDrawBuffers
+        if (extensionEnabled(WebGLDrawBuffersName)
             && pname >= GL_DRAW_BUFFER0_EXT
             && pname < static_cast<GLenum>(GL_DRAW_BUFFER0_EXT + maxDrawBuffers())) {
             GLint value = GL_NONE;
             if (m_framebufferBinding)
                 value = m_framebufferBinding->getDrawBuffer(pname);
             else // emulated backbuffer
                 value = m_backDrawBuffer;
             return WebGLGetInfo(value);
         }
         synthesizeGLError(GL_INVALID_ENUM, "getParameter", "invalid parameter name");
         return WebGLGetInfo();
     }
 }
 
-WebGLGetInfo WebGLRenderingContext::getProgramParameter(WebGLProgram* program, GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getProgramParameter(WebGLProgram* program, GLenum pname)
 {
     if (isContextLost() || !validateWebGLObject("getProgramParameter", program))
         return WebGLGetInfo();
 
     GLint value = 0;
     switch (pname) {
     case GL_DELETE_STATUS:
         return WebGLGetInfo(program->isDeleted());
     case GL_VALIDATE_STATUS:
         m_context->getProgramiv(objectOrZero(program), pname, &value);
         return WebGLGetInfo(static_cast<bool>(value));
     case GL_LINK_STATUS:
         return WebGLGetInfo(program->linkStatus());
     case GL_ATTACHED_SHADERS:
     case GL_ACTIVE_ATTRIBUTES:
     case GL_ACTIVE_UNIFORMS:
         m_context->getProgramiv(objectOrZero(program), pname, &value);
         return WebGLGetInfo(value);
     default:
         synthesizeGLError(GL_INVALID_ENUM, "getProgramParameter", "invalid parameter name");
         return WebGLGetInfo();
     }
 }
 
-String WebGLRenderingContext::getProgramInfoLog(WebGLProgram* program)
+String WebGLRenderingContextBase::getProgramInfoLog(WebGLProgram* program)
 {
     if (isContextLost())
         return String();
     if (!validateWebGLObject("getProgramInfoLog", program))
         return "";
     return ensureNotNull(m_context->getProgramInfoLog(objectOrZero(program)));
 }
 
-WebGLGetInfo WebGLRenderingContext::getRenderbufferParameter(GLenum target, GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getRenderbufferParameter(GLenum target, GLenum pname)
 {
     if (isContextLost())
         return WebGLGetInfo();
     if (target != GL_RENDERBUFFER) {
         synthesizeGLError(GL_INVALID_ENUM, "getRenderbufferParameter", "invalid target");
         return WebGLGetInfo();
     }
     if (!m_renderbufferBinding || !m_renderbufferBinding->object()) {
         synthesizeGLError(GL_INVALID_OPERATION, "getRenderbufferParameter", "no renderbuffer bound");
         return WebGLGetInfo();
@@ skipping 20 matching lines @@
         }
         return WebGLGetInfo(value);
     case GL_RENDERBUFFER_INTERNAL_FORMAT:
         return WebGLGetInfo(m_renderbufferBinding->internalFormat());
     default:
         synthesizeGLError(GL_INVALID_ENUM, "getRenderbufferParameter", "invalid parameter name");
         return WebGLGetInfo();
     }
 }
 
-WebGLGetInfo WebGLRenderingContext::getShaderParameter(WebGLShader* shader, GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getShaderParameter(WebGLShader* shader, GLenum pname)
 {
     if (isContextLost() || !validateWebGLObject("getShaderParameter", shader))
         return WebGLGetInfo();
     GLint value = 0;
     switch (pname) {
     case GL_DELETE_STATUS:
         return WebGLGetInfo(shader->isDeleted());
     case GL_COMPILE_STATUS:
         m_context->getShaderiv(objectOrZero(shader), pname, &value);
         return WebGLGetInfo(static_cast<bool>(value));
     case GL_SHADER_TYPE:
         m_context->getShaderiv(objectOrZero(shader), pname, &value);
         return WebGLGetInfo(static_cast<unsigned>(value));
     default:
         synthesizeGLError(GL_INVALID_ENUM, "getShaderParameter", "invalid parameter name");
         return WebGLGetInfo();
     }
 }
 
-String WebGLRenderingContext::getShaderInfoLog(WebGLShader* shader)
+String WebGLRenderingContextBase::getShaderInfoLog(WebGLShader* shader)
 {
     if (isContextLost())
         return String();
     if (!validateWebGLObject("getShaderInfoLog", shader))
         return "";
     return ensureNotNull(m_context->getShaderInfoLog(objectOrZero(shader)));
 }
 
-PassRefPtr<WebGLShaderPrecisionFormat> WebGLRenderingContext::getShaderPrecisionFormat(GLenum shaderType, GLenum precisionType)
+PassRefPtr<WebGLShaderPrecisionFormat> WebGLRenderingContextBase::getShaderPrecisionFormat(GLenum shaderType, GLenum precisionType)
 {
     if (isContextLost())
         return nullptr;
     switch (shaderType) {
     case GL_VERTEX_SHADER:
     case GL_FRAGMENT_SHADER:
         break;
     default:
         synthesizeGLError(GL_INVALID_ENUM, "getShaderPrecisionFormat", "invalid shader type");
         return nullptr;
@@ skipping 10 matching lines @@
         synthesizeGLError(GL_INVALID_ENUM, "getShaderPrecisionFormat", "invalid precision type");
         return nullptr;
     }
 
     GLint range[2] = {0, 0};
     GLint precision = 0;
     m_context->getShaderPrecisionFormat(shaderType, precisionType, range, &precision);
     return WebGLShaderPrecisionFormat::create(range[0], range[1], precision);
 }
 
-String WebGLRenderingContext::getShaderSource(WebGLShader* shader)
+String WebGLRenderingContextBase::getShaderSource(WebGLShader* shader)
 {
     if (isContextLost())
         return String();
     if (!validateWebGLObject("getShaderSource", shader))
         return "";
     return ensureNotNull(shader->source());
 }
 
-Vector<String> WebGLRenderingContext::getSupportedExtensions()
+Vector<String> WebGLRenderingContextBase::getSupportedExtensions()
 {
     Vector<String> result;
     if (isContextLost())
         return result;
 
     for (size_t i = 0; i < m_extensions.size(); ++i) {
         ExtensionTracker* tracker = m_extensions[i];
         if (tracker->webglDebugRendererInfo() && !allowWebGLDebugRendererInfo())
             continue;
         if (tracker->privileged() && !allowPrivilegedExtensions())
             continue;
         if (tracker->draft() && !RuntimeEnabledFeatures::webGLDraftExtensionsEnabled())
             continue;
         if (tracker->supported(this))
             result.append(String(tracker->prefixed()  ? "WEBKIT_" : "") + tracker->extensionName());
     }
 
     return result;
 }
 
-WebGLGetInfo WebGLRenderingContext::getTexParameter(GLenum target, GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getTexParameter(GLenum target, GLenum pname)
 {
     if (isContextLost())
         return WebGLGetInfo();
     WebGLTexture* tex = validateTextureBinding("getTexParameter", target, false);
     if (!tex)
         return WebGLGetInfo();
     GLint value = 0;
     switch (pname) {
     case GL_TEXTURE_MAG_FILTER:
     case GL_TEXTURE_MIN_FILTER:
     case GL_TEXTURE_WRAP_S:
     case GL_TEXTURE_WRAP_T:
         m_context->getTexParameteriv(target, pname, &value);
         return WebGLGetInfo(static_cast<unsigned>(value));
     case GL_TEXTURE_MAX_ANISOTROPY_EXT: // EXT_texture_filter_anisotropic
-        if (m_extTextureFilterAnisotropic) {
+        if (extensionEnabled(EXTTextureFilterAnisotropicName)) {
             m_context->getTexParameteriv(target, pname, &value);
             return WebGLGetInfo(static_cast<unsigned>(value));
         }
         synthesizeGLError(GL_INVALID_ENUM, "getTexParameter", "invalid parameter name, EXT_texture_filter_anisotropic not enabled");
         return WebGLGetInfo();
     default:
         synthesizeGLError(GL_INVALID_ENUM, "getTexParameter", "invalid parameter name");
         return WebGLGetInfo();
     }
 }
 
-WebGLGetInfo WebGLRenderingContext::getUniform(WebGLProgram* program, const WebGLUniformLocation* uniformLocation)
+WebGLGetInfo WebGLRenderingContextBase::getUniform(WebGLProgram* program, const WebGLUniformLocation* uniformLocation)
 {
     if (isContextLost() || !validateWebGLObject("getUniform", program))
         return WebGLGetInfo();
     if (!uniformLocation || uniformLocation->program() != program) {
         synthesizeGLError(GL_INVALID_OPERATION, "getUniform", "no uniformlocation or not valid for this program");
         return WebGLGetInfo();
     }
     GLint location = uniformLocation->location();
 
     // FIXME: make this more efficient using WebGLUniformLocation and caching types in it
@@ skipping 124 matching lines @@
                     notImplemented();
                 }
             }
         }
     }
     // If we get here, something went wrong in our unfortunately complex logic above
     synthesizeGLError(GL_INVALID_VALUE, "getUniform", "unknown error");
     return WebGLGetInfo();
 }
 
-PassRefPtr<WebGLUniformLocation> WebGLRenderingContext::getUniformLocation(WebGLProgram* program, const String& name)
+PassRefPtr<WebGLUniformLocation> WebGLRenderingContextBase::getUniformLocation(WebGLProgram* program, const String& name)
 {
     if (isContextLost() || !validateWebGLObject("getUniformLocation", program))
         return nullptr;
     if (!validateLocationLength("getUniformLocation", name))
         return nullptr;
     if (!validateString("getUniformLocation", name))
         return nullptr;
     if (isPrefixReserved(name))
         return nullptr;
     if (!program->linkStatus()) {
         synthesizeGLError(GL_INVALID_OPERATION, "getUniformLocation", "program not linked");
         return nullptr;
     }
     GLint uniformLocation = m_context->getUniformLocation(objectOrZero(program), name.utf8().data());
     if (uniformLocation == -1)
         return nullptr;
     return WebGLUniformLocation::create(program, uniformLocation);
 }
 
-WebGLGetInfo WebGLRenderingContext::getVertexAttrib(GLuint index, GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getVertexAttrib(GLuint index, GLenum pname)
 {
     if (isContextLost())
         return WebGLGetInfo();
     if (index >= m_maxVertexAttribs) {
         synthesizeGLError(GL_INVALID_VALUE, "getVertexAttrib", "index out of range");
         return WebGLGetInfo();
     }
     const WebGLVertexArrayObjectOES::VertexAttribState& state = m_boundVertexArrayObject->getVertexAttribState(index);
 
-    if (m_angleInstancedArrays && pname == GL_VERTEX_ATTRIB_ARRAY_DIVISOR_ANGLE)
+    if (extensionEnabled(ANGLEInstancedArraysName) && pname == GL_VERTEX_ATTRIB_ARRAY_DIVISOR_ANGLE)
         return WebGLGetInfo(state.divisor);
 
     switch (pname) {
     case GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING:
         if (!state.bufferBinding || !state.bufferBinding->object())
             return WebGLGetInfo();
         return WebGLGetInfo(PassRefPtr<WebGLBuffer>(state.bufferBinding));
     case GL_VERTEX_ATTRIB_ARRAY_ENABLED:
         return WebGLGetInfo(state.enabled);
     case GL_VERTEX_ATTRIB_ARRAY_NORMALIZED:
         return WebGLGetInfo(state.normalized);
     case GL_VERTEX_ATTRIB_ARRAY_SIZE:
         return WebGLGetInfo(state.size);
     case GL_VERTEX_ATTRIB_ARRAY_STRIDE:
         return WebGLGetInfo(state.originalStride);
     case GL_VERTEX_ATTRIB_ARRAY_TYPE:
         return WebGLGetInfo(state.type);
     case GL_CURRENT_VERTEX_ATTRIB:
         return WebGLGetInfo(Float32Array::create(m_vertexAttribValue[index].value, 4));
     default:
         synthesizeGLError(GL_INVALID_ENUM, "getVertexAttrib", "invalid parameter name");
         return WebGLGetInfo();
     }
 }
 
-long long WebGLRenderingContext::getVertexAttribOffset(GLuint index, GLenum pname)
+long long WebGLRenderingContextBase::getVertexAttribOffset(GLuint index, GLenum pname)
 {
     if (isContextLost())
         return 0;
     if (pname != GL_VERTEX_ATTRIB_ARRAY_POINTER) {
         synthesizeGLError(GL_INVALID_ENUM, "getVertexAttribOffset", "invalid parameter name");
         return 0;
     }
     GLsizeiptr result = m_context->getVertexAttribOffset(index, pname);
     return static_cast<long long>(result);
 }
 
-void WebGLRenderingContext::hint(GLenum target, GLenum mode)
+void WebGLRenderingContextBase::hint(GLenum target, GLenum mode)
 {
     if (isContextLost())
         return;
     bool isValid = false;
     switch (target) {
     case GL_GENERATE_MIPMAP_HINT:
         isValid = true;
         break;
     case GL_FRAGMENT_SHADER_DERIVATIVE_HINT_OES: // OES_standard_derivatives
-        if (m_oesStandardDerivatives)
+        if (extensionEnabled(OESStandardDerivativesName))
             isValid = true;
         break;
     }
     if (!isValid) {
         synthesizeGLError(GL_INVALID_ENUM, "hint", "invalid target");
         return;
     }
     m_context->hint(target, mode);
 }
 
-GLboolean WebGLRenderingContext::isBuffer(WebGLBuffer* buffer)
+GLboolean WebGLRenderingContextBase::isBuffer(WebGLBuffer* buffer)
 {
     if (!buffer || isContextLost())
         return 0;
 
     if (!buffer->hasEverBeenBound())
         return 0;
 
     return m_context->isBuffer(buffer->object());
 }
 
-bool WebGLRenderingContext::isContextLost()
+bool WebGLRenderingContextBase::isContextLost()
 {
     return m_contextLost;
 }
 
-GLboolean WebGLRenderingContext::isEnabled(GLenum cap)
+GLboolean WebGLRenderingContextBase::isEnabled(GLenum cap)
 {
     if (isContextLost() || !validateCapability("isEnabled", cap))
         return 0;
     if (cap == GL_STENCIL_TEST)
         return m_stencilEnabled;
     return m_context->isEnabled(cap);
 }
 
-GLboolean WebGLRenderingContext::isFramebuffer(WebGLFramebuffer* framebuffer)
+GLboolean WebGLRenderingContextBase::isFramebuffer(WebGLFramebuffer* framebuffer)
 {
     if (!framebuffer || isContextLost())
         return 0;
 
     if (!framebuffer->hasEverBeenBound())
         return 0;
 
     return m_context->isFramebuffer(framebuffer->object());
 }
 
-GLboolean WebGLRenderingContext::isProgram(WebGLProgram* program)
+GLboolean WebGLRenderingContextBase::isProgram(WebGLProgram* program)
 {
     if (!program || isContextLost())
         return 0;
 
     return m_context->isProgram(program->object());
 }
 
-GLboolean WebGLRenderingContext::isRenderbuffer(WebGLRenderbuffer* renderbuffer)
+GLboolean WebGLRenderingContextBase::isRenderbuffer(WebGLRenderbuffer* renderbuffer)
 {
     if (!renderbuffer || isContextLost())
         return 0;
 
     if (!renderbuffer->hasEverBeenBound())
         return 0;
 
     return m_context->isRenderbuffer(renderbuffer->object());
 }
 
-GLboolean WebGLRenderingContext::isShader(WebGLShader* shader)
+GLboolean WebGLRenderingContextBase::isShader(WebGLShader* shader)
 {
     if (!shader || isContextLost())
         return 0;
 
     return m_context->isShader(shader->object());
 }
 
-GLboolean WebGLRenderingContext::isTexture(WebGLTexture* texture)
+GLboolean WebGLRenderingContextBase::isTexture(WebGLTexture* texture)
 {
     if (!texture || isContextLost())
         return 0;
 
     if (!texture->hasEverBeenBound())
         return 0;
 
     return m_context->isTexture(texture->object());
 }
 
-void WebGLRenderingContext::lineWidth(GLfloat width)
+void WebGLRenderingContextBase::lineWidth(GLfloat width)
 {
     if (isContextLost())
         return;
     m_context->lineWidth(width);
 }
 
-void WebGLRenderingContext::linkProgram(WebGLProgram* program)
+void WebGLRenderingContextBase::linkProgram(WebGLProgram* program)
 {
     if (isContextLost() || !validateWebGLObject("linkProgram", program))
         return;
 
     m_context->linkProgram(objectOrZero(program));
     program->increaseLinkCount();
 }
 
-void WebGLRenderingContext::pixelStorei(GLenum pname, GLint param)
+void WebGLRenderingContextBase::pixelStorei(GLenum pname, GLint param)
 {
     if (isContextLost())
         return;
     switch (pname) {
     case GC3D_UNPACK_FLIP_Y_WEBGL:
         m_unpackFlipY = param;
         break;
     case GC3D_UNPACK_PREMULTIPLY_ALPHA_WEBGL:
         m_unpackPremultiplyAlpha = param;
         break;
@@ skipping 19 matching lines @@
             synthesizeGLError(GL_INVALID_VALUE, "pixelStorei", "invalid parameter for alignment");
             return;
         }
         break;
     default:
         synthesizeGLError(GL_INVALID_ENUM, "pixelStorei", "invalid parameter name");
         return;
     }
 }
 
-void WebGLRenderingContext::polygonOffset(GLfloat factor, GLfloat units)
+void WebGLRenderingContextBase::polygonOffset(GLfloat factor, GLfloat units)
 {
     if (isContextLost())
         return;
     m_context->polygonOffset(factor, units);
 }
 
-void WebGLRenderingContext::readPixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, ArrayBufferView* pixels)
+void WebGLRenderingContextBase::readPixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, ArrayBufferView* pixels)
 {
     if (isContextLost())
         return;
     // Due to WebGL's same-origin restrictions, it is not possible to
     // taint the origin using the WebGL API.
     ASSERT(canvas()->originClean());
     // Validate input parameters.
     if (!pixels) {
         synthesizeGLError(GL_INVALID_VALUE, "readPixels", "no destination ArrayBufferView");
         return;
@@ skipping 61 matching lines @@
             for (GLsizei ix = 0; ix < width; ++ix) {
                 pixels[3] = 255;
                 pixels += 4;
             }
             pixels += padding;
         }
     }
 #endif
 }
 
-void WebGLRenderingContext::renderbufferStorage(GLenum target, GLenum internalformat, GLsizei width, GLsizei height)
+void WebGLRenderingContextBase::renderbufferStorage(GLenum target, GLenum internalformat, GLsizei width, GLsizei height)
 {
     if (isContextLost())
         return;
     if (target != GL_RENDERBUFFER) {
         synthesizeGLError(GL_INVALID_ENUM, "renderbufferStorage", "invalid target");
         return;
     }
     if (!m_renderbufferBinding || !m_renderbufferBinding->object()) {
         synthesizeGLError(GL_INVALID_OPERATION, "renderbufferStorage", "no bound renderbuffer");
         return;
@@ skipping 30 matching lines @@
         m_renderbufferBinding->setSize(width, height);
         m_renderbufferBinding->setInternalFormat(internalformat);
         break;
     default:
         synthesizeGLError(GL_INVALID_ENUM, "renderbufferStorage", "invalid internalformat");
         return;
     }
     applyStencilTest();
 }
 
-void WebGLRenderingContext::sampleCoverage(GLfloat value, GLboolean invert)
+void WebGLRenderingContextBase::sampleCoverage(GLfloat value, GLboolean invert)
 {
     if (isContextLost())
         return;
     m_context->sampleCoverage(value, invert);
 }
 
-void WebGLRenderingContext::scissor(GLint x, GLint y, GLsizei width, GLsizei height)
+void WebGLRenderingContextBase::scissor(GLint x, GLint y, GLsizei width, GLsizei height)
 {
     if (isContextLost())
         return;
     if (!validateSize("scissor", width, height))
         return;
     m_context->scissor(x, y, width, height);
 }
 
-void WebGLRenderingContext::shaderSource(WebGLShader* shader, const String& string)
+void WebGLRenderingContextBase::shaderSource(WebGLShader* shader, const String& string)
 {
     if (isContextLost() || !validateWebGLObject("shaderSource", shader))
         return;
     String stringWithoutComments = StripComments(string).result();
     if (!validateString("shaderSource", stringWithoutComments))
         return;
     shader->setSource(string);
     m_context->shaderSource(objectOrZero(shader), stringWithoutComments.utf8().data());
 }
 
-void WebGLRenderingContext::stencilFunc(GLenum func, GLint ref, GLuint mask)
+void WebGLRenderingContextBase::stencilFunc(GLenum func, GLint ref, GLuint mask)
 {
     if (isContextLost())
         return;
     if (!validateStencilOrDepthFunc("stencilFunc", func))
         return;
     m_stencilFuncRef = ref;
     m_stencilFuncRefBack = ref;
     m_stencilFuncMask = mask;
     m_stencilFuncMaskBack = mask;
     m_context->stencilFunc(func, ref, mask);
 }
 
-void WebGLRenderingContext::stencilFuncSeparate(GLenum face, GLenum func, GLint ref, GLuint mask)
+void WebGLRenderingContextBase::stencilFuncSeparate(GLenum face, GLenum func, GLint ref, GLuint mask)
 {
     if (isContextLost())
         return;
     if (!validateStencilOrDepthFunc("stencilFuncSeparate", func))
         return;
     switch (face) {
     case GL_FRONT_AND_BACK:
         m_stencilFuncRef = ref;
         m_stencilFuncRefBack = ref;
         m_stencilFuncMask = mask;
         m_stencilFuncMaskBack = mask;
         break;
     case GL_FRONT:
         m_stencilFuncRef = ref;
         m_stencilFuncMask = mask;
         break;
     case GL_BACK:
         m_stencilFuncRefBack = ref;
         m_stencilFuncMaskBack = mask;
         break;
     default:
         synthesizeGLError(GL_INVALID_ENUM, "stencilFuncSeparate", "invalid face");
         return;
     }
     m_context->stencilFuncSeparate(face, func, ref, mask);
 }
 
-void WebGLRenderingContext::stencilMask(GLuint mask)
+void WebGLRenderingContextBase::stencilMask(GLuint mask)
 {
     if (isContextLost())
         return;
     m_stencilMask = mask;
     m_stencilMaskBack = mask;
     m_context->stencilMask(mask);
 }
 
-void WebGLRenderingContext::stencilMaskSeparate(GLenum face, GLuint mask)
+void WebGLRenderingContextBase::stencilMaskSeparate(GLenum face, GLuint mask)
 {
     if (isContextLost())
         return;
     switch (face) {
     case GL_FRONT_AND_BACK:
         m_stencilMask = mask;
         m_stencilMaskBack = mask;
         break;
     case GL_FRONT:
         m_stencilMask = mask;
         break;
     case GL_BACK:
         m_stencilMaskBack = mask;
         break;
     default:
         synthesizeGLError(GL_INVALID_ENUM, "stencilMaskSeparate", "invalid face");
         return;
     }
     m_context->stencilMaskSeparate(face, mask);
 }
 
-void WebGLRenderingContext::stencilOp(GLenum fail, GLenum zfail, GLenum zpass)
+void WebGLRenderingContextBase::stencilOp(GLenum fail, GLenum zfail, GLenum zpass)
 {
     if (isContextLost())
         return;
     m_context->stencilOp(fail, zfail, zpass);
 }
 
-void WebGLRenderingContext::stencilOpSeparate(GLenum face, GLenum fail, GLenum zfail, GLenum zpass)
+void WebGLRenderingContextBase::stencilOpSeparate(GLenum face, GLenum fail, GLenum zfail, GLenum zpass)
 {
     if (isContextLost())
         return;
     m_context->stencilOpSeparate(face, fail, zfail, zpass);
 }
 
-GLenum WebGLRenderingContext::convertTexInternalFormat(GLenum internalformat, GLenum type)
+GLenum WebGLRenderingContextBase::convertTexInternalFormat(GLenum internalformat, GLenum type)
 {
     // Convert to sized internal formats that are renderable with GL_CHROMIUM_color_buffer_float_rgb(a).
     if (type == GL_FLOAT && internalformat == GL_RGBA
         && extensionsUtil()->isExtensionEnabled("GL_CHROMIUM_color_buffer_float_rgba"))
         return GL_RGBA32F_EXT;
     if (type == GL_FLOAT && internalformat == GL_RGB
         && extensionsUtil()->isExtensionEnabled("GL_CHROMIUM_color_buffer_float_rgb"))
         return GL_RGB32F_EXT;
     return internalformat;
 }
 
-void WebGLRenderingContext::texImage2DBase(GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, const void* pixels, ExceptionState& exceptionState)
+void WebGLRenderingContextBase::texImage2DBase(GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, const void* pixels, ExceptionState& exceptionState)
 {
     // All calling functions check isContextLost, so a duplicate check is not needed here.
     // FIXME: Handle errors.
     WebGLTexture* tex = validateTextureBinding("texImage2D", target, true);
     ASSERT(validateTexFuncParameters("texImage2D", NotTexSubImage2D, target, level, internalformat, width, height, border, format, type));
     ASSERT(tex);
     ASSERT(!level || !WebGLTexture::isNPOT(width, height));
     ASSERT(!pixels || validateSettableTexFormat("texImage2D", internalformat));
     m_context->texImage2D(target, level, convertTexInternalFormat(internalformat, type), width, height, border, format, type, pixels);
     tex->setLevelInfo(target, level, internalformat, width, height, type);
 }
 
-void WebGLRenderingContext::texImage2DImpl(GLenum target, GLint level, GLenum internalformat, GLenum format, GLenum type, Image* image, WebGLImageConversion::ImageHtmlDomSource domSource, bool flipY, bool premultiplyAlpha, ExceptionState& exceptionState)
+void WebGLRenderingContextBase::texImage2DImpl(GLenum target, GLint level, GLenum internalformat, GLenum format, GLenum type, Image* image, WebGLImageConversion::ImageHtmlDomSource domSource, bool flipY, bool premultiplyAlpha, ExceptionState& exceptionState)
 {
     // All calling functions check isContextLost, so a duplicate check is not needed here.
     Vector<uint8_t> data;
     WebGLImageConversion::ImageExtractor imageExtractor(image, domSource, premultiplyAlpha, m_unpackColorspaceConversion == GL_NONE);
     if (!imageExtractor.extractSucceeded()) {
         synthesizeGLError(GL_INVALID_VALUE, "texImage2D", "bad image data");
         return;
     }
     WebGLImageConversion::DataFormat sourceDataFormat = imageExtractor.imageSourceFormat();
     WebGLImageConversion::AlphaOp alphaOp = imageExtractor.imageAlphaOp();
     const void* imagePixelData = imageExtractor.imagePixelData();
 
     bool needConversion = true;
     if (type == GL_UNSIGNED_BYTE && sourceDataFormat == WebGLImageConversion::DataFormatRGBA8 && format == GL_RGBA && alphaOp == WebGLImageConversion::AlphaDoNothing && !flipY)
         needConversion = false;
     else {
         if (!WebGLImageConversion::packImageData(image, imagePixelData, format, type, flipY, alphaOp, sourceDataFormat, imageExtractor.imageWidth(), imageExtractor.imageHeight(), imageExtractor.imageSourceUnpackAlignment(), data)) {
             synthesizeGLError(GL_INVALID_VALUE, "texImage2D", "packImage error");
             return;
         }
     }
 
     if (m_unpackAlignment != 1)
         m_context->pixelStorei(GL_UNPACK_ALIGNMENT, 1);
     texImage2DBase(target, level, internalformat, image->width(), image->height(), 0, format, type, needConversion ? data.data() : imagePixelData, exceptionState);
     if (m_unpackAlignment != 1)
         m_context->pixelStorei(GL_UNPACK_ALIGNMENT, m_unpackAlignment);
 }
 
-bool WebGLRenderingContext::validateTexFunc(const char* functionName, TexFuncValidationFunctionType functionType, TexFuncValidationSourceType sourceType, GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, GLint xoffset, GLint yoffset)
+bool WebGLRenderingContextBase::validateTexFunc(const char* functionName, TexFuncValidationFunctionType functionType, TexFuncValidationSourceType sourceType, GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, GLint xoffset, GLint yoffset)
 {
     if (!validateTexFuncParameters(functionName, functionType, target, level, internalformat, width, height, border, format, type))
         return false;
 
     WebGLTexture* texture = validateTextureBinding(functionName, target, true);
     if (!texture)
         return false;
 
     if (functionType == NotTexSubImage2D) {
         if (level && WebGLTexture::isNPOT(width, height)) {
@@ skipping 22 matching lines @@
         }
         if (texture->getInternalFormat(target, level) != format || texture->getType(target, level) != type) {
             synthesizeGLError(GL_INVALID_OPERATION, functionName, "type and format do not match texture");
             return false;
         }
     }
 
     return true;
 }
 
-PassRefPtr<Image> WebGLRenderingContext::drawImageIntoBuffer(Image* image, int width, int height)
+PassRefPtr<Image> WebGLRenderingContextBase::drawImageIntoBuffer(Image* image, int width, int height)
 {
     IntSize size(width, height);
     ImageBuffer* buf = m_generatedImageCache.imageBuffer(size);
     if (!buf) {
         synthesizeGLError(GL_OUT_OF_MEMORY, "texImage2D", "out of memory");
         return nullptr;
     }
 
     IntRect srcRect(IntPoint(), image->size());
     IntRect destRect(0, 0, size.width(), size.height());
     buf->context()->drawImage(image, destRect, srcRect);
     return buf->copyImage(ImageBuffer::fastCopyImageMode());
 }
 
-void WebGLRenderingContext::texImage2D(GLenum target, GLint level, GLenum internalformat,
+void WebGLRenderingContextBase::texImage2D(GLenum target, GLint level, GLenum internalformat,
     GLsizei width, GLsizei height, GLint border,
     GLenum format, GLenum type, ArrayBufferView* pixels, ExceptionState& exceptionState)
 {
     if (isContextLost() || !validateTexFuncData("texImage2D", level, width, height, format, type, pixels, NullAllowed)
         || !validateTexFunc("texImage2D", NotTexSubImage2D, SourceArrayBufferView, target, level, internalformat, width, height, border, format, type, 0, 0))
         return;
     void* data = pixels ? pixels->baseAddress() : 0;
     Vector<uint8_t> tempData;
     bool changeUnpackAlignment = false;
     if (data && (m_unpackFlipY || m_unpackPremultiplyAlpha)) {
         if (!WebGLImageConversion::extractTextureData(width, height, format, type, m_unpackAlignment, m_unpackFlipY, m_unpackPremultiplyAlpha, data, tempData))
             return;
         data = tempData.data();
         changeUnpackAlignment = true;
     }
     if (changeUnpackAlignment)
         m_context->pixelStorei(GL_UNPACK_ALIGNMENT, 1);
     texImage2DBase(target, level, internalformat, width, height, border, format, type, data, exceptionState);
     if (changeUnpackAlignment)
         m_context->pixelStorei(GL_UNPACK_ALIGNMENT, m_unpackAlignment);
 }
 
-void WebGLRenderingContext::texImage2D(GLenum target, GLint level, GLenum internalformat,
+void WebGLRenderingContextBase::texImage2D(GLenum target, GLint level, GLenum internalformat,
     GLenum format, GLenum type, ImageData* pixels, ExceptionState& exceptionState)
 {
     if (isContextLost() || !pixels || !validateTexFunc("texImage2D", NotTexSubImage2D, SourceImageData, target, level, internalformat, pixels->width(), pixels->height(), 0, format, type, 0, 0))
         return;
     Vector<uint8_t> data;
     bool needConversion = true;
     // The data from ImageData is always of format RGBA8.
     // No conversion is needed if destination format is RGBA and type is USIGNED_BYTE and no Flip or Premultiply operation is required.
     if (!m_unpackFlipY && !m_unpackPremultiplyAlpha && format == GL_RGBA && type == GL_UNSIGNED_BYTE)
         needConversion = false;
     else {
         if (!WebGLImageConversion::extractImageData(pixels->data()->data(), pixels->size(), format, type, m_unpackFlipY, m_unpackPremultiplyAlpha, data)) {
             synthesizeGLError(GL_INVALID_VALUE, "texImage2D", "bad image data");
             return;
         }
     }
     if (m_unpackAlignment != 1)
         m_context->pixelStorei(GL_UNPACK_ALIGNMENT, 1);
     texImage2DBase(target, level, internalformat, pixels->width(), pixels->height(), 0, format, type, needConversion ? data.data() : pixels->data()->data(), exceptionState);
     if (m_unpackAlignment != 1)
         m_context->pixelStorei(GL_UNPACK_ALIGNMENT, m_unpackAlignment);
 }
 
-void WebGLRenderingContext::texImage2D(GLenum target, GLint level, GLenum internalformat,
+void WebGLRenderingContextBase::texImage2D(GLenum target, GLint level, GLenum internalformat,
     GLenum format, GLenum type, HTMLImageElement* image, ExceptionState& exceptionState)
 {
     if (isContextLost() || !validateHTMLImageElement("texImage2D", image, exceptionState))
         return;
 
     RefPtr<Image> imageForRender = image->cachedImage()->imageForRenderer(image->renderer());
     if (imageForRender->isSVGImage())
         imageForRender = drawImageIntoBuffer(imageForRender.get(), image->width(), image->height());
 
     if (!imageForRender || !validateTexFunc("texImage2D", NotTexSubImage2D, SourceHTMLImageElement, target, level, internalformat, imageForRender->width(), imageForRender->height(), 0, format, type, 0, 0))
         return;
 
     texImage2DImpl(target, level, internalformat, format, type, imageForRender.get(), WebGLImageConversion::HtmlDomImage, m_unpackFlipY, m_unpackPremultiplyAlpha, exceptionState);
 }
 
-void WebGLRenderingContext::texImage2D(GLenum target, GLint level, GLenum internalformat,
+void WebGLRenderingContextBase::texImage2D(GLenum target, GLint level, GLenum internalformat,
     GLenum format, GLenum type, HTMLCanvasElement* canvas, ExceptionState& exceptionState)
 {
     if (isContextLost() || !validateHTMLCanvasElement("texImage2D", canvas, exceptionState) || !validateTexFunc("texImage2D", NotTexSubImage2D, SourceHTMLCanvasElement, target, level, internalformat, canvas->width(), canvas->height(), 0, format, type, 0, 0))
         return;
 
     WebGLTexture* texture = validateTextureBinding("texImage2D", target, true);
     // If possible, copy from the canvas element directly to the texture
     // via the GPU, without a read-back to system memory.
     if (GL_TEXTURE_2D == target && texture) {
         if (!canvas->is3D()) {
             ImageBuffer* buffer = canvas->buffer();
             if (buffer && buffer->copyToPlatformTexture(m_context.get(), texture->object(), internalformat, type,
                 level, m_unpackPremultiplyAlpha, m_unpackFlipY)) {
                 texture->setLevelInfo(target, level, internalformat, canvas->width(), canvas->height(), type);
                 return;
             }
         } else {
-            WebGLRenderingContext* gl = toWebGLRenderingContext(canvas->renderingContext());
+            WebGLRenderingContextBase* gl = toWebGLRenderingContextBase(canvas->renderingContext());
             if (gl && gl->m_drawingBuffer->copyToPlatformTexture(m_context.get(), texture->object(), internalformat, type,
                 level, m_unpackPremultiplyAlpha, m_unpackFlipY)) {
                 texture->setLevelInfo(target, level, internalformat, canvas->width(), canvas->height(), type);
                 return;
             }
         }
     }
 
     RefPtr<ImageData> imageData = canvas->getImageData();
     if (imageData)
         texImage2D(target, level, internalformat, format, type, imageData.get(), exceptionState);
     else
         texImage2DImpl(target, level, internalformat, format, type, canvas->copiedImage(), WebGLImageConversion::HtmlDomCanvas, m_unpackFlipY, m_unpackPremultiplyAlpha, exceptionState);
 }
 
-PassRefPtr<Image> WebGLRenderingContext::videoFrameToImage(HTMLVideoElement* video, BackingStoreCopy backingStoreCopy)
+PassRefPtr<Image> WebGLRenderingContextBase::videoFrameToImage(HTMLVideoElement* video, BackingStoreCopy backingStoreCopy)
 {
     IntSize size(video->videoWidth(), video->videoHeight());
     ImageBuffer* buf = m_generatedImageCache.imageBuffer(size);
     if (!buf) {
         synthesizeGLError(GL_OUT_OF_MEMORY, "texImage2D", "out of memory");
         return nullptr;
     }
     IntRect destRect(0, 0, size.width(), size.height());
     // FIXME: Turn this into a GPU-GPU texture copy instead of CPU readback.
     video->paintCurrentFrameInContext(buf->context(), destRect);
     return buf->copyImage(backingStoreCopy);
 }
 
-void WebGLRenderingContext::texImage2D(GLenum target, GLint level, GLenum internalformat,
+void WebGLRenderingContextBase::texImage2D(GLenum target, GLint level, GLenum internalformat,
     GLenum format, GLenum type, HTMLVideoElement* video, ExceptionState& exceptionState)
 {
     if (isContextLost() || !validateHTMLVideoElement("texImage2D", video, exceptionState)
         || !validateTexFunc("texImage2D", NotTexSubImage2D, SourceHTMLVideoElement, target, level, internalformat, video->videoWidth(), video->videoHeight(), 0, format, type, 0, 0))
         return;
 
     // Go through the fast path doing a GPU-GPU textures copy without a readback to system memory if possible.
     // Otherwise, it will fall back to the normal SW path.
     WebGLTexture* texture = validateTextureBinding("texImage2D", target, true);
     if (GL_TEXTURE_2D == target && texture) {
         if (video->copyVideoTextureToPlatformTexture(m_context.get(), texture->object(), level, type, internalformat, m_unpackPremultiplyAlpha, m_unpackFlipY)) {
             texture->setLevelInfo(target, level, internalformat, video->videoWidth(), video->videoHeight(), type);
             return;
         }
     }
 
     // Normal pure SW path.
     RefPtr<Image> image = videoFrameToImage(video, ImageBuffer::fastCopyImageMode());
     if (!image)
         return;
     texImage2DImpl(target, level, internalformat, format, type, image.get(), WebGLImageConversion::HtmlDomVideo, m_unpackFlipY, m_unpackPremultiplyAlpha, exceptionState);
 }
 
-void WebGLRenderingContext::texParameter(GLenum target, GLenum pname, GLfloat paramf, GLint parami, bool isFloat)
+void WebGLRenderingContextBase::texParameter(GLenum target, GLenum pname, GLfloat paramf, GLint parami, bool isFloat)
 {
     if (isContextLost())
         return;
     WebGLTexture* tex = validateTextureBinding("texParameter", target, false);
     if (!tex)
         return;
     switch (pname) {
     case GL_TEXTURE_MIN_FILTER:
     case GL_TEXTURE_MAG_FILTER:
         break;
     case GL_TEXTURE_WRAP_S:
     case GL_TEXTURE_WRAP_T:
         if ((isFloat && paramf != GL_CLAMP_TO_EDGE && paramf != GL_MIRRORED_REPEAT && paramf != GL_REPEAT)
             || (!isFloat && parami != GL_CLAMP_TO_EDGE && parami != GL_MIRRORED_REPEAT && parami != GL_REPEAT)) {
             synthesizeGLError(GL_INVALID_ENUM, "texParameter", "invalid parameter");
             return;
         }
         break;
     case GL_TEXTURE_MAX_ANISOTROPY_EXT: // EXT_texture_filter_anisotropic
-        if (!m_extTextureFilterAnisotropic) {
+        if (!extensionEnabled(EXTTextureFilterAnisotropicName)) {
             synthesizeGLError(GL_INVALID_ENUM, "texParameter", "invalid parameter, EXT_texture_filter_anisotropic not enabled");
             return;
         }
         break;
     default:
         synthesizeGLError(GL_INVALID_ENUM, "texParameter", "invalid parameter name");
         return;
     }
     if (isFloat) {
         tex->setParameterf(pname, paramf);
         m_context->texParameterf(target, pname, paramf);
     } else {
         tex->setParameteri(pname, parami);
         m_context->texParameteri(target, pname, parami);
     }
 }
 
-void WebGLRenderingContext::texParameterf(GLenum target, GLenum pname, GLfloat param)
+void WebGLRenderingContextBase::texParameterf(GLenum target, GLenum pname, GLfloat param)
 {
     texParameter(target, pname, param, 0, true);
 }
 
-void WebGLRenderingContext::texParameteri(GLenum target, GLenum pname, GLint param)
+void WebGLRenderingContextBase::texParameteri(GLenum target, GLenum pname, GLint param)
 {
     texParameter(target, pname, 0, param, false);
 }
 
-void WebGLRenderingContext::texSubImage2DBase(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLenum type, const void* pixels, ExceptionState& exceptionState)
+void WebGLRenderingContextBase::texSubImage2DBase(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLenum type, const void* pixels, ExceptionState& exceptionState)
 {
     // FIXME: Handle errors.
     ASSERT(!isContextLost());
     ASSERT(validateTexFuncParameters("texSubImage2D", TexSubImage2D, target, level, format, width, height, 0, format, type));
     ASSERT(validateSize("texSubImage2D", xoffset, yoffset));
     ASSERT(validateSettableTexFormat("texSubImage2D", format));
     WebGLTexture* tex = validateTextureBinding("texSubImage2D", target, true);
     if (!tex) {
         ASSERT_NOT_REACHED();
         return;
     }
     ASSERT((xoffset + width) >= 0);
     ASSERT((yoffset + height) >= 0);
     ASSERT(tex->getWidth(target, level) >= (xoffset + width));
     ASSERT(tex->getHeight(target, level) >= (yoffset + height));
     ASSERT(tex->getInternalFormat(target, level) == format);
     ASSERT(tex->getType(target, level) == type);
     m_context->texSubImage2D(target, level, xoffset, yoffset, width, height, format, type, pixels);
 }
 
-void WebGLRenderingContext::texSubImage2DImpl(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLenum format, GLenum type, Image* image, WebGLImageConversion::ImageHtmlDomSource domSource, bool flipY, bool premultiplyAlpha, ExceptionState& exceptionState)
+void WebGLRenderingContextBase::texSubImage2DImpl(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLenum format, GLenum type, Image* image, WebGLImageConversion::ImageHtmlDomSource domSource, bool flipY, bool premultiplyAlpha, ExceptionState& exceptionState)
 {
     // All calling functions check isContextLost, so a duplicate check is not needed here.
     Vector<uint8_t> data;
     WebGLImageConversion::ImageExtractor imageExtractor(image, domSource, premultiplyAlpha, m_unpackColorspaceConversion == GL_NONE);
     if (!imageExtractor.extractSucceeded()) {
         synthesizeGLError(GL_INVALID_VALUE, "texSubImage2D", "bad image");
         return;
     }
     WebGLImageConversion::DataFormat sourceDataFormat = imageExtractor.imageSourceFormat();
     WebGLImageConversion::AlphaOp alphaOp = imageExtractor.imageAlphaOp();
     const void* imagePixelData = imageExtractor.imagePixelData();
 
     bool needConversion = true;
     if (type == GL_UNSIGNED_BYTE && sourceDataFormat == WebGLImageConversion::DataFormatRGBA8 && format == GL_RGBA && alphaOp == WebGLImageConversion::AlphaDoNothing && !flipY)
         needConversion = false;
     else {
         if (!WebGLImageConversion::packImageData(image, imagePixelData, format, type, flipY, alphaOp, sourceDataFormat, imageExtractor.imageWidth(), imageExtractor.imageHeight(), imageExtractor.imageSourceUnpackAlignment(), data)) {
             synthesizeGLError(GL_INVALID_VALUE, "texImage2D", "bad image data");
             return;
         }
     }
 
     if (m_unpackAlignment != 1)
         m_context->pixelStorei(GL_UNPACK_ALIGNMENT, 1);
     texSubImage2DBase(target, level, xoffset, yoffset, image->width(), image->height(), format, type,  needConversion ? data.data() : imagePixelData, exceptionState);
     if (m_unpackAlignment != 1)
         m_context->pixelStorei(GL_UNPACK_ALIGNMENT, m_unpackAlignment);
 }
 
-void WebGLRenderingContext::texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,
+void WebGLRenderingContextBase::texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,
     GLsizei width, GLsizei height,
     GLenum format, GLenum type, ArrayBufferView* pixels, ExceptionState& exceptionState)
 {
     if (isContextLost() || !validateTexFuncData("texSubImage2D", level, width, height, format, type, pixels, NullNotAllowed)
         || !validateTexFunc("texSubImage2D", TexSubImage2D, SourceArrayBufferView, target, level, format, width, height, 0, format, type, xoffset, yoffset))
         return;
     void* data = pixels->baseAddress();
     Vector<uint8_t> tempData;
     bool changeUnpackAlignment = false;
     if (data && (m_unpackFlipY || m_unpackPremultiplyAlpha)) {
         if (!WebGLImageConversion::extractTextureData(width, height, format, type,
                                            m_unpackAlignment,
                                            m_unpackFlipY, m_unpackPremultiplyAlpha,
                                            data,
                                            tempData))
             return;
         data = tempData.data();
         changeUnpackAlignment = true;
     }
     if (changeUnpackAlignment)
         m_context->pixelStorei(GL_UNPACK_ALIGNMENT, 1);
     texSubImage2DBase(target, level, xoffset, yoffset, width, height, format, type, data, exceptionState);
     if (changeUnpackAlignment)
         m_context->pixelStorei(GL_UNPACK_ALIGNMENT, m_unpackAlignment);
 }
 
-void WebGLRenderingContext::texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,
+void WebGLRenderingContextBase::texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,
     GLenum format, GLenum type, ImageData* pixels, ExceptionState& exceptionState)
 {
     if (isContextLost() || !pixels || !validateTexFunc("texSubImage2D", TexSubImage2D, SourceImageData, target, level, format,  pixels->width(), pixels->height(), 0, format, type, xoffset, yoffset))
         return;
 
     Vector<uint8_t> data;
     bool needConversion = true;
     // The data from ImageData is always of format RGBA8.
     // No conversion is needed if destination format is RGBA and type is USIGNED_BYTE and no Flip or Premultiply operation is required.
     if (format == GL_RGBA && type == GL_UNSIGNED_BYTE && !m_unpackFlipY && !m_unpackPremultiplyAlpha)
         needConversion = false;
     else {
         if (!WebGLImageConversion::extractImageData(pixels->data()->data(), pixels->size(), format, type, m_unpackFlipY, m_unpackPremultiplyAlpha, data)) {
             synthesizeGLError(GL_INVALID_VALUE, "texSubImage2D", "bad image data");
             return;
         }
     }
     if (m_unpackAlignment != 1)
         m_context->pixelStorei(GL_UNPACK_ALIGNMENT, 1);
     texSubImage2DBase(target, level, xoffset, yoffset, pixels->width(), pixels->height(), format, type, needConversion ? data.data() : pixels->data()->data(), exceptionState);
     if (m_unpackAlignment != 1)
         m_context->pixelStorei(GL_UNPACK_ALIGNMENT, m_unpackAlignment);
 }
 
-void WebGLRenderingContext::texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,
+void WebGLRenderingContextBase::texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,
     GLenum format, GLenum type, HTMLImageElement* image, ExceptionState& exceptionState)
 {
     if (isContextLost() || !validateHTMLImageElement("texSubImage2D", image, exceptionState))
         return;
 
     RefPtr<Image> imageForRender = image->cachedImage()->imageForRenderer(image->renderer());
     if (imageForRender->isSVGImage())
         imageForRender = drawImageIntoBuffer(imageForRender.get(), image->width(), image->height());
 
     if (!imageForRender || !validateTexFunc("texSubImage2D", TexSubImage2D, SourceHTMLImageElement, target, level, format, imageForRender->width(), imageForRender->height(), 0, format, type, xoffset, yoffset))
         return;
 
     texSubImage2DImpl(target, level, xoffset, yoffset, format, type, imageForRender.get(), WebGLImageConversion::HtmlDomImage, m_unpackFlipY, m_unpackPremultiplyAlpha, exceptionState);
 }
 
-void WebGLRenderingContext::texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,
+void WebGLRenderingContextBase::texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,
     GLenum format, GLenum type, HTMLCanvasElement* canvas, ExceptionState& exceptionState)
 {
     if (isContextLost() || !validateHTMLCanvasElement("texSubImage2D", canvas, exceptionState)
         || !validateTexFunc("texSubImage2D", TexSubImage2D, SourceHTMLCanvasElement, target, level, format, canvas->width(), canvas->height(), 0, format, type, xoffset, yoffset))
         return;
 
     RefPtr<ImageData> imageData = canvas->getImageData();
     if (imageData)
         texSubImage2D(target, level, xoffset, yoffset, format, type, imageData.get(), exceptionState);
     else
         texSubImage2DImpl(target, level, xoffset, yoffset, format, type, canvas->copiedImage(), WebGLImageConversion::HtmlDomCanvas, m_unpackFlipY, m_unpackPremultiplyAlpha, exceptionState);
 }
 
-void WebGLRenderingContext::texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,
+void WebGLRenderingContextBase::texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,
     GLenum format, GLenum type, HTMLVideoElement* video, ExceptionState& exceptionState)
 {
     if (isContextLost() || !validateHTMLVideoElement("texSubImage2D", video, exceptionState)
         || !validateTexFunc("texSubImage2D", TexSubImage2D, SourceHTMLVideoElement, target, level, format, video->videoWidth(), video->videoHeight(), 0, format, type, xoffset, yoffset))
         return;
 
     RefPtr<Image> image = videoFrameToImage(video, ImageBuffer::fastCopyImageMode());
     if (!image)
         return;
     texSubImage2DImpl(target, level, xoffset, yoffset, format, type, image.get(), WebGLImageConversion::HtmlDomVideo, m_unpackFlipY, m_unpackPremultiplyAlpha, exceptionState);
 }
 
-void WebGLRenderingContext::uniform1f(const WebGLUniformLocation* location, GLfloat x)
+void WebGLRenderingContextBase::uniform1f(const WebGLUniformLocation* location, GLfloat x)
 {
     if (isContextLost() || !location)
         return;
 
     if (location->program() != m_currentProgram) {
         synthesizeGLError(GL_INVALID_OPERATION, "uniform1f", "location not for current program");
         return;
     }
 
     m_context->uniform1f(location->location(), x);
 }
 
-void WebGLRenderingContext::uniform1fv(const WebGLUniformLocation* location, Float32Array* v)
+void WebGLRenderingContextBase::uniform1fv(const WebGLUniformLocation* location, Float32Array* v)
 {
     if (isContextLost() || !validateUniformParameters("uniform1fv", location, v, 1))
         return;
 
     m_context->uniform1fv(location->location(), v->length(), v->data());
 }
 
-void WebGLRenderingContext::uniform1fv(const WebGLUniformLocation* location, GLfloat* v, GLsizei size)
+void WebGLRenderingContextBase::uniform1fv(const WebGLUniformLocation* location, GLfloat* v, GLsizei size)
 {
     if (isContextLost() || !validateUniformParameters("uniform1fv", location, v, size, 1))
         return;
 
     m_context->uniform1fv(location->location(), size, v);
 }
 
-void WebGLRenderingContext::uniform1i(const WebGLUniformLocation* location, GLint x)
+void WebGLRenderingContextBase::uniform1i(const WebGLUniformLocation* location, GLint x)
 {
     if (isContextLost() || !location)
         return;
 
     if (location->program() != m_currentProgram) {
         synthesizeGLError(GL_INVALID_OPERATION, "uniform1i", "location not for current program");
         return;
     }
 
     m_context->uniform1i(location->location(), x);
 }
 
-void WebGLRenderingContext::uniform1iv(const WebGLUniformLocation* location, Int32Array* v)
+void WebGLRenderingContextBase::uniform1iv(const WebGLUniformLocation* location, Int32Array* v)
 {
     if (isContextLost() || !validateUniformParameters("uniform1iv", location, v, 1))
         return;
 
     m_context->uniform1iv(location->location(), v->length(), v->data());
 }
 
-void WebGLRenderingContext::uniform1iv(const WebGLUniformLocation* location, GLint* v, GLsizei size)
+void WebGLRenderingContextBase::uniform1iv(const WebGLUniformLocation* location, GLint* v, GLsizei size)
 {
     if (isContextLost() || !validateUniformParameters("uniform1iv", location, v, size, 1))
         return;
 
     m_context->uniform1iv(location->location(), size, v);
 }
 
-void WebGLRenderingContext::uniform2f(const WebGLUniformLocation* location, GLfloat x, GLfloat y)
+void WebGLRenderingContextBase::uniform2f(const WebGLUniformLocation* location, GLfloat x, GLfloat y)
 {
     if (isContextLost() || !location)
         return;
 
     if (location->program() != m_currentProgram) {
         synthesizeGLError(GL_INVALID_OPERATION, "uniform2f", "location not for current program");
         return;
     }
 
     m_context->uniform2f(location->location(), x, y);
 }
 
-void WebGLRenderingContext::uniform2fv(const WebGLUniformLocation* location, Float32Array* v)
+void WebGLRenderingContextBase::uniform2fv(const WebGLUniformLocation* location, Float32Array* v)
 {
     if (isContextLost() || !validateUniformParameters("uniform2fv", location, v, 2))
         return;
 
     m_context->uniform2fv(location->location(), v->length() / 2, v->data());
 }
 
-void WebGLRenderingContext::uniform2fv(const WebGLUniformLocation* location, GLfloat* v, GLsizei size)
+void WebGLRenderingContextBase::uniform2fv(const WebGLUniformLocation* location, GLfloat* v, GLsizei size)
 {
     if (isContextLost() || !validateUniformParameters("uniform2fv", location, v, size, 2))
         return;
 
     m_context->uniform2fv(location->location(), size / 2, v);
 }
 
-void WebGLRenderingContext::uniform2i(const WebGLUniformLocation* location, GLint x, GLint y)
+void WebGLRenderingContextBase::uniform2i(const WebGLUniformLocation* location, GLint x, GLint y)
 {
     if (isContextLost() || !location)
         return;
 
     if (location->program() != m_currentProgram) {
         synthesizeGLError(GL_INVALID_OPERATION, "uniform2i", "location not for current program");
         return;
     }
 
     m_context->uniform2i(location->location(), x, y);
 }
 
-void WebGLRenderingContext::uniform2iv(const WebGLUniformLocation* location, Int32Array* v)
+void WebGLRenderingContextBase::uniform2iv(const WebGLUniformLocation* location, Int32Array* v)
 {
     if (isContextLost() || !validateUniformParameters("uniform2iv", location, v, 2))
         return;
 
     m_context->uniform2iv(location->location(), v->length() / 2, v->data());
 }
 
-void WebGLRenderingContext::uniform2iv(const WebGLUniformLocation* location, GLint* v, GLsizei size)
+void WebGLRenderingContextBase::uniform2iv(const WebGLUniformLocation* location, GLint* v, GLsizei size)
 {
     if (isContextLost() || !validateUniformParameters("uniform2iv", location, v, size, 2))
         return;
 
     m_context->uniform2iv(location->location(), size / 2, v);
 }
 
-void WebGLRenderingContext::uniform3f(const WebGLUniformLocation* location, GLfloat x, GLfloat y, GLfloat z)
+void WebGLRenderingContextBase::uniform3f(const WebGLUniformLocation* location, GLfloat x, GLfloat y, GLfloat z)
 {
     if (isContextLost() || !location)
         return;
 
     if (location->program() != m_currentProgram) {
         synthesizeGLError(GL_INVALID_OPERATION, "uniform3f", "location not for current program");
         return;
     }
 
     m_context->uniform3f(location->location(), x, y, z);
 }
 
-void WebGLRenderingContext::uniform3fv(const WebGLUniformLocation* location, Float32Array* v)
+void WebGLRenderingContextBase::uniform3fv(const WebGLUniformLocation* location, Float32Array* v)
 {
     if (isContextLost() || !validateUniformParameters("uniform3fv", location, v, 3))
         return;
 
     m_context->uniform3fv(location->location(), v->length() / 3, v->data());
 }
 
-void WebGLRenderingContext::uniform3fv(const WebGLUniformLocation* location, GLfloat* v, GLsizei size)
+void WebGLRenderingContextBase::uniform3fv(const WebGLUniformLocation* location, GLfloat* v, GLsizei size)
 {
     if (isContextLost() || !validateUniformParameters("uniform3fv", location, v, size, 3))
         return;
 
     m_context->uniform3fv(location->location(), size / 3, v);
 }
 
-void WebGLRenderingContext::uniform3i(const WebGLUniformLocation* location, GLint x, GLint y, GLint z)
+void WebGLRenderingContextBase::uniform3i(const WebGLUniformLocation* location, GLint x, GLint y, GLint z)
 {
     if (isContextLost() || !location)
         return;
 
     if (location->program() != m_currentProgram) {
         synthesizeGLError(GL_INVALID_OPERATION, "uniform3i", "location not for current program");
         return;
     }
 
     m_context->uniform3i(location->location(), x, y, z);
 }
 
-void WebGLRenderingContext::uniform3iv(const WebGLUniformLocation* location, Int32Array* v)
+void WebGLRenderingContextBase::uniform3iv(const WebGLUniformLocation* location, Int32Array* v)
 {
     if (isContextLost() || !validateUniformParameters("uniform3iv", location, v, 3))
         return;
 
     m_context->uniform3iv(location->location(), v->length() / 3, v->data());
 }
 
-void WebGLRenderingContext::uniform3iv(const WebGLUniformLocation* location, GLint* v, GLsizei size)
+void WebGLRenderingContextBase::uniform3iv(const WebGLUniformLocation* location, GLint* v, GLsizei size)
 {
     if (isContextLost() || !validateUniformParameters("uniform3iv", location, v, size, 3))
         return;
 
     m_context->uniform3iv(location->location(), size / 3, v);
 }
 
-void WebGLRenderingContext::uniform4f(const WebGLUniformLocation* location, GLfloat x, GLfloat y, GLfloat z, GLfloat w)
+void WebGLRenderingContextBase::uniform4f(const WebGLUniformLocation* location, GLfloat x, GLfloat y, GLfloat z, GLfloat w)
 {
     if (isContextLost() || !location)
         return;
 
     if (location->program() != m_currentProgram) {
         synthesizeGLError(GL_INVALID_OPERATION, "uniform4f", "location not for current program");
         return;
     }
 
     m_context->uniform4f(location->location(), x, y, z, w);
 }
 
-void WebGLRenderingContext::uniform4fv(const WebGLUniformLocation* location, Float32Array* v)
+void WebGLRenderingContextBase::uniform4fv(const WebGLUniformLocation* location, Float32Array* v)
 {
     if (isContextLost() || !validateUniformParameters("uniform4fv", location, v, 4))
         return;
 
     m_context->uniform4fv(location->location(), v->length() / 4, v->data());
 }
 
-void WebGLRenderingContext::uniform4fv(const WebGLUniformLocation* location, GLfloat* v, GLsizei size)
+void WebGLRenderingContextBase::uniform4fv(const WebGLUniformLocation* location, GLfloat* v, GLsizei size)
 {
     if (isContextLost() || !validateUniformParameters("uniform4fv", location, v, size, 4))
         return;
 
     m_context->uniform4fv(location->location(), size / 4, v);
 }
 
-void WebGLRenderingContext::uniform4i(const WebGLUniformLocation* location, GLint x, GLint y, GLint z, GLint w)
+void WebGLRenderingContextBase::uniform4i(const WebGLUniformLocation* location, GLint x, GLint y, GLint z, GLint w)
 {
     if (isContextLost() || !location)
         return;
 
     if (location->program() != m_currentProgram) {
         synthesizeGLError(GL_INVALID_OPERATION, "uniform4i", "location not for current program");
         return;
     }
 
     m_context->uniform4i(location->location(), x, y, z, w);
 }
 
-void WebGLRenderingContext::uniform4iv(const WebGLUniformLocation* location, Int32Array* v)
+void WebGLRenderingContextBase::uniform4iv(const WebGLUniformLocation* location, Int32Array* v)
 {
     if (isContextLost() || !validateUniformParameters("uniform4iv", location, v, 4))
         return;
 
     m_context->uniform4iv(location->location(), v->length() / 4, v->data());
 }
 
-void WebGLRenderingContext::uniform4iv(const WebGLUniformLocation* location, GLint* v, GLsizei size)
+void WebGLRenderingContextBase::uniform4iv(const WebGLUniformLocation* location, GLint* v, GLsizei size)
 {
     if (isContextLost() || !validateUniformParameters("uniform4iv", location, v, size, 4))
         return;
 
     m_context->uniform4iv(location->location(), size / 4, v);
 }
 
-void WebGLRenderingContext::uniformMatrix2fv(const WebGLUniformLocation* location, GLboolean transpose, Float32Array* v)
+void WebGLRenderingContextBase::uniformMatrix2fv(const WebGLUniformLocation* location, GLboolean transpose, Float32Array* v)
 {
     if (isContextLost() || !validateUniformMatrixParameters("uniformMatrix2fv", location, transpose, v, 4))
         return;
     m_context->uniformMatrix2fv(location->location(), v->length() / 4, transpose, v->data());
 }
 
-void WebGLRenderingContext::uniformMatrix2fv(const WebGLUniformLocation* location, GLboolean transpose, GLfloat* v, GLsizei size)
+void WebGLRenderingContextBase::uniformMatrix2fv(const WebGLUniformLocation* location, GLboolean transpose, GLfloat* v, GLsizei size)
 {
     if (isContextLost() || !validateUniformMatrixParameters("uniformMatrix2fv", location, transpose, v, size, 4))
         return;
     m_context->uniformMatrix2fv(location->location(), size / 4, transpose, v);
 }
 
-void WebGLRenderingContext::uniformMatrix3fv(const WebGLUniformLocation* location, GLboolean transpose, Float32Array* v)
+void WebGLRenderingContextBase::uniformMatrix3fv(const WebGLUniformLocation* location, GLboolean transpose, Float32Array* v)
 {
     if (isContextLost() || !validateUniformMatrixParameters("uniformMatrix3fv", location, transpose, v, 9))
         return;
     m_context->uniformMatrix3fv(location->location(), v->length() / 9, transpose, v->data());
 }
 
-void WebGLRenderingContext::uniformMatrix3fv(const WebGLUniformLocation* location, GLboolean transpose, GLfloat* v, GLsizei size)
+void WebGLRenderingContextBase::uniformMatrix3fv(const WebGLUniformLocation* location, GLboolean transpose, GLfloat* v, GLsizei size)
 {
     if (isContextLost() || !validateUniformMatrixParameters("uniformMatrix3fv", location, transpose, v, size, 9))
         return;
     m_context->uniformMatrix3fv(location->location(), size / 9, transpose, v);
 }
 
-void WebGLRenderingContext::uniformMatrix4fv(const WebGLUniformLocation* location, GLboolean transpose, Float32Array* v)
+void WebGLRenderingContextBase::uniformMatrix4fv(const WebGLUniformLocation* location, GLboolean transpose, Float32Array* v)
 {
     if (isContextLost() || !validateUniformMatrixParameters("uniformMatrix4fv", location, transpose, v, 16))
         return;
     m_context->uniformMatrix4fv(location->location(), v->length() / 16, transpose, v->data());
 }
 
-void WebGLRenderingContext::uniformMatrix4fv(const WebGLUniformLocation* location, GLboolean transpose, GLfloat* v, GLsizei size)
+void WebGLRenderingContextBase::uniformMatrix4fv(const WebGLUniformLocation* location, GLboolean transpose, GLfloat* v, GLsizei size)
 {
     if (isContextLost() || !validateUniformMatrixParameters("uniformMatrix4fv", location, transpose, v, size, 16))
         return;
     m_context->uniformMatrix4fv(location->location(), size / 16, transpose, v);
 }
 
-void WebGLRenderingContext::useProgram(WebGLProgram* program)
+void WebGLRenderingContextBase::useProgram(WebGLProgram* program)
 {
     bool deleted;
     if (!checkObjectToBeBound("useProgram", program, deleted))
         return;
     if (deleted)
         program = 0;
     if (program && !program->linkStatus()) {
         synthesizeGLError(GL_INVALID_OPERATION, "useProgram", "program not valid");
         return;
     }
     if (m_currentProgram != program) {
         if (m_currentProgram)
             m_currentProgram->onDetached(m_context.get());
         m_currentProgram = program;
         m_context->useProgram(objectOrZero(program));
         if (program)
             program->onAttached();
     }
 }
 
-void WebGLRenderingContext::validateProgram(WebGLProgram* program)
+void WebGLRenderingContextBase::validateProgram(WebGLProgram* program)
 {
     if (isContextLost() || !validateWebGLObject("validateProgram", program))
         return;
     m_context->validateProgram(objectOrZero(program));
 }
 
-void WebGLRenderingContext::vertexAttrib1f(GLuint index, GLfloat v0)
+void WebGLRenderingContextBase::vertexAttrib1f(GLuint index, GLfloat v0)
 {
     vertexAttribfImpl("vertexAttrib1f", index, 1, v0, 0.0f, 0.0f, 1.0f);
 }
 
-void WebGLRenderingContext::vertexAttrib1fv(GLuint index, Float32Array* v)
+void WebGLRenderingContextBase::vertexAttrib1fv(GLuint index, Float32Array* v)
 {
     vertexAttribfvImpl("vertexAttrib1fv", index, v, 1);
 }
 
-void WebGLRenderingContext::vertexAttrib1fv(GLuint index, GLfloat* v, GLsizei size)
+void WebGLRenderingContextBase::vertexAttrib1fv(GLuint index, GLfloat* v, GLsizei size)
 {
     vertexAttribfvImpl("vertexAttrib1fv", index, v, size, 1);
 }
 
-void WebGLRenderingContext::vertexAttrib2f(GLuint index, GLfloat v0, GLfloat v1)
+void WebGLRenderingContextBase::vertexAttrib2f(GLuint index, GLfloat v0, GLfloat v1)
 {
     vertexAttribfImpl("vertexAttrib2f", index, 2, v0, v1, 0.0f, 1.0f);
 }
 
-void WebGLRenderingContext::vertexAttrib2fv(GLuint index, Float32Array* v)
+void WebGLRenderingContextBase::vertexAttrib2fv(GLuint index, Float32Array* v)
 {
     vertexAttribfvImpl("vertexAttrib2fv", index, v, 2);
 }
 
-void WebGLRenderingContext::vertexAttrib2fv(GLuint index, GLfloat* v, GLsizei size)
+void WebGLRenderingContextBase::vertexAttrib2fv(GLuint index, GLfloat* v, GLsizei size)
 {
     vertexAttribfvImpl("vertexAttrib2fv", index, v, size, 2);
 }
 
-void WebGLRenderingContext::vertexAttrib3f(GLuint index, GLfloat v0, GLfloat v1, GLfloat v2)
+void WebGLRenderingContextBase::vertexAttrib3f(GLuint index, GLfloat v0, GLfloat v1, GLfloat v2)
 {
     vertexAttribfImpl("vertexAttrib3f", index, 3, v0, v1, v2, 1.0f);
 }
 
-void WebGLRenderingContext::vertexAttrib3fv(GLuint index, Float32Array* v)
+void WebGLRenderingContextBase::vertexAttrib3fv(GLuint index, Float32Array* v)
 {
     vertexAttribfvImpl("vertexAttrib3fv", index, v, 3);
 }
 
-void WebGLRenderingContext::vertexAttrib3fv(GLuint index, GLfloat* v, GLsizei size)
+void WebGLRenderingContextBase::vertexAttrib3fv(GLuint index, GLfloat* v, GLsizei size)
 {
     vertexAttribfvImpl("vertexAttrib3fv", index, v, size, 3);
 }
 
-void WebGLRenderingContext::vertexAttrib4f(GLuint index, GLfloat v0, GLfloat v1, GLfloat v2, GLfloat v3)
+void WebGLRenderingContextBase::vertexAttrib4f(GLuint index, GLfloat v0, GLfloat v1, GLfloat v2, GLfloat v3)
 {
     vertexAttribfImpl("vertexAttrib4f", index, 4, v0, v1, v2, v3);
 }
 
-void WebGLRenderingContext::vertexAttrib4fv(GLuint index, Float32Array* v)
+void WebGLRenderingContextBase::vertexAttrib4fv(GLuint index, Float32Array* v)
 {
     vertexAttribfvImpl("vertexAttrib4fv", index, v, 4);
 }
 
-void WebGLRenderingContext::vertexAttrib4fv(GLuint index, GLfloat* v, GLsizei size)
+void WebGLRenderingContextBase::vertexAttrib4fv(GLuint index, GLfloat* v, GLsizei size)
 {
     vertexAttribfvImpl("vertexAttrib4fv", index, v, size, 4);
 }
 
-void WebGLRenderingContext::vertexAttribPointer(GLuint index, GLint size, GLenum type, GLboolean normalized, GLsizei stride, long long offset)
+void WebGLRenderingContextBase::vertexAttribPointer(GLuint index, GLint size, GLenum type, GLboolean normalized, GLsizei stride, long long offset)
 {
     if (isContextLost())
         return;
     switch (type) {
     case GL_BYTE:
     case GL_UNSIGNED_BYTE:
     case GL_SHORT:
     case GL_UNSIGNED_SHORT:
     case GL_FLOAT:
         break;
@@ skipping 22 matching lines @@
     if ((stride % typeSize) || (static_cast<GLintptr>(offset) % typeSize)) {
         synthesizeGLError(GL_INVALID_OPERATION, "vertexAttribPointer", "stride or offset not valid for type");
         return;
     }
     GLsizei bytesPerElement = size * typeSize;
 
     m_boundVertexArrayObject->setVertexAttribState(index, bytesPerElement, size, type, normalized, stride, static_cast<GLintptr>(offset), m_boundArrayBuffer);
     m_context->vertexAttribPointer(index, size, type, normalized, stride, static_cast<GLintptr>(offset));
 }
 
-void WebGLRenderingContext::vertexAttribDivisorANGLE(GLuint index, GLuint divisor)
+void WebGLRenderingContextBase::vertexAttribDivisorANGLE(GLuint index, GLuint divisor)
 {
     if (isContextLost())
         return;
 
     if (index >= m_maxVertexAttribs) {
         synthesizeGLError(GL_INVALID_VALUE, "vertexAttribDivisorANGLE", "index out of range");
         return;
     }
 
     m_boundVertexArrayObject->setVertexAttribDivisor(index, divisor);
     m_context->vertexAttribDivisorANGLE(index, divisor);
 }
 
-void WebGLRenderingContext::viewport(GLint x, GLint y, GLsizei width, GLsizei height)
+void WebGLRenderingContextBase::viewport(GLint x, GLint y, GLsizei width, GLsizei height)
 {
     if (isContextLost())
         return;
     if (!validateSize("viewport", width, height))
         return;
     m_context->viewport(x, y, width, height);
 }
 
-void WebGLRenderingContext::forceLostContext(WebGLRenderingContext::LostContextMode mode)
+void WebGLRenderingContextBase::forceLostContext(WebGLRenderingContextBase::LostContextMode mode)
 {
     if (isContextLost()) {
         synthesizeGLError(GL_INVALID_OPERATION, "loseContext", "context already lost");
         return;
     }
 
     m_contextGroup->loseContextGroup(mode);
 }
 
-void WebGLRenderingContext::loseContextImpl(WebGLRenderingContext::LostContextMode mode)
+void WebGLRenderingContextBase::loseContextImpl(WebGLRenderingContextBase::LostContextMode mode)
 {
     if (isContextLost())
         return;
 
     m_contextLost = true;
     m_contextLostMode = mode;
 
     if (mode == RealLostContext) {
         // Inform the embedder that a lost context was received. In response, the embedder might
         // decide to take action such as asking the user for permission to use WebGL again.
         if (Frame* frame = canvas()->document().frame())
             frame->loader().client()->didLoseWebGLContext(m_context->getGraphicsResetStatusARB());
     }
 
     // Make absolutely sure we do not refer to an already-deleted texture or framebuffer.
     m_drawingBuffer->setTexture2DBinding(0);
     m_drawingBuffer->setFramebufferBinding(0);
 
     detachAndRemoveAllObjects();
 
     // Lose all the extensions.
     for (size_t i = 0; i < m_extensions.size(); ++i) {
         ExtensionTracker* tracker = m_extensions[i];
         tracker->loseExtension();
     }
 
+    for (size_t i = 0; i < WebGLExtensionNameCount; ++i)
+        m_extensionEnabled[i] = false;
+
     removeAllCompressedTextureFormats();
 
     if (mode != RealLostContext)
         destroyContext();
 
     ConsoleDisplayPreference display = (mode == RealLostContext) ? DisplayInConsole: DontDisplayInConsole;
     synthesizeGLError(GC3D_CONTEXT_LOST_WEBGL, "loseContext", "context lost", display);
 
     // Don't allow restoration unless the context lost event has both been
     // dispatched and its default behavior prevented.
     m_restoreAllowed = false;
 
     // Always defer the dispatch of the context lost event, to implement
     // the spec behavior of queueing a task.
     m_dispatchContextLostEventTimer.startOneShot(0);
 }
 
-void WebGLRenderingContext::forceRestoreContext()
+void WebGLRenderingContextBase::forceRestoreContext()
 {
     if (!isContextLost()) {
         synthesizeGLError(GL_INVALID_OPERATION, "restoreContext", "context not lost");
         return;
     }
 
     if (!m_restoreAllowed) {
         if (m_contextLostMode == SyntheticLostContext)
             synthesizeGLError(GL_INVALID_OPERATION, "restoreContext", "context restoration not allowed");
         return;
     }
 
     if (!m_restoreTimer.isActive())
         m_restoreTimer.startOneShot(0);
 }
 
-blink::WebLayer* WebGLRenderingContext::platformLayer() const
+blink::WebLayer* WebGLRenderingContextBase::platformLayer() const
 {
     return m_drawingBuffer->platformLayer();
 }
 
-Extensions3DUtil* WebGLRenderingContext::extensionsUtil()
+Extensions3DUtil* WebGLRenderingContextBase::extensionsUtil()
 {
     if (!m_extensionsUtil)
         m_extensionsUtil = adoptPtr(new Extensions3DUtil(m_context.get()));
     return m_extensionsUtil.get();
 }
 
-void WebGLRenderingContext::removeSharedObject(WebGLSharedObject* object)
+void WebGLRenderingContextBase::removeSharedObject(WebGLSharedObject* object)
 {
     m_contextGroup->removeObject(object);
 }
 
-void WebGLRenderingContext::addSharedObject(WebGLSharedObject* object)
+void WebGLRenderingContextBase::addSharedObject(WebGLSharedObject* object)
 {
     ASSERT(!isContextLost());
     m_contextGroup->addObject(object);
 }
 
-void WebGLRenderingContext::removeContextObject(WebGLContextObject* object)
+void WebGLRenderingContextBase::removeContextObject(WebGLContextObject* object)
 {
     m_contextObjects.remove(object);
 }
 
-void WebGLRenderingContext::addContextObject(WebGLContextObject* object)
+void WebGLRenderingContextBase::addContextObject(WebGLContextObject* object)
 {
     ASSERT(!isContextLost());
     m_contextObjects.add(object);
 }
 
-void WebGLRenderingContext::detachAndRemoveAllObjects()
+void WebGLRenderingContextBase::detachAndRemoveAllObjects()
 {
     while (m_contextObjects.size() > 0) {
         HashSet<WebGLContextObject*>::iterator it = m_contextObjects.begin();
         (*it)->detachContext();
     }
 }
 
-bool WebGLRenderingContext::hasPendingActivity() const
+bool WebGLRenderingContextBase::hasPendingActivity() const
 {
     return false;
 }
 
-void WebGLRenderingContext::stop()
+void WebGLRenderingContextBase::stop()
 {
     if (!isContextLost()) {
         forceLostContext(SyntheticLostContext);
         destroyContext();
     }
 }
 
-WebGLGetInfo WebGLRenderingContext::getBooleanParameter(GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getBooleanParameter(GLenum pname)
 {
     GLboolean value = 0;
     if (!isContextLost())
         m_context->getBooleanv(pname, &value);
     return WebGLGetInfo(static_cast<bool>(value));
 }
 
-WebGLGetInfo WebGLRenderingContext::getBooleanArrayParameter(GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getBooleanArrayParameter(GLenum pname)
 {
     if (pname != GL_COLOR_WRITEMASK) {
         notImplemented();
         return WebGLGetInfo(0, 0);
     }
     GLboolean value[4] = {0};
     if (!isContextLost())
         m_context->getBooleanv(pname, value);
     bool boolValue[4];
     for (int ii = 0; ii < 4; ++ii)
         boolValue[ii] = static_cast<bool>(value[ii]);
     return WebGLGetInfo(boolValue, 4);
 }
 
-WebGLGetInfo WebGLRenderingContext::getFloatParameter(GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getFloatParameter(GLenum pname)
 {
     GLfloat value = 0;
     if (!isContextLost())
         m_context->getFloatv(pname, &value);
     return WebGLGetInfo(value);
 }
 
-WebGLGetInfo WebGLRenderingContext::getIntParameter(GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getIntParameter(GLenum pname)
 {
     GLint value = 0;
     if (!isContextLost())
         m_context->getIntegerv(pname, &value);
     return WebGLGetInfo(value);
 }
 
-WebGLGetInfo WebGLRenderingContext::getUnsignedIntParameter(GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getUnsignedIntParameter(GLenum pname)
 {
     GLint value = 0;
     if (!isContextLost())
         m_context->getIntegerv(pname, &value);
     return WebGLGetInfo(static_cast<unsigned>(value));
 }
 
-WebGLGetInfo WebGLRenderingContext::getWebGLFloatArrayParameter(GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getWebGLFloatArrayParameter(GLenum pname)
 {
     GLfloat value[4] = {0};
     if (!isContextLost())
         m_context->getFloatv(pname, value);
     unsigned length = 0;
     switch (pname) {
     case GL_ALIASED_POINT_SIZE_RANGE:
     case GL_ALIASED_LINE_WIDTH_RANGE:
     case GL_DEPTH_RANGE:
         length = 2;
         break;
     case GL_BLEND_COLOR:
     case GL_COLOR_CLEAR_VALUE:
         length = 4;
         break;
     default:
         notImplemented();
     }
     return WebGLGetInfo(Float32Array::create(value, length));
 }
 
-WebGLGetInfo WebGLRenderingContext::getWebGLIntArrayParameter(GLenum pname)
+WebGLGetInfo WebGLRenderingContextBase::getWebGLIntArrayParameter(GLenum pname)
 {
     GLint value[4] = {0};
     if (!isContextLost())
         m_context->getIntegerv(pname, value);
     unsigned length = 0;
     switch (pname) {
     case GL_MAX_VIEWPORT_DIMS:
         length = 2;
         break;
     case GL_SCISSOR_BOX:
     case GL_VIEWPORT:
         length = 4;
         break;
     default:
         notImplemented();
     }
     return WebGLGetInfo(Int32Array::create(value, length));
 }
 
-void WebGLRenderingContext::handleTextureCompleteness(const char* functionName, bool prepareToDraw)
+void WebGLRenderingContextBase::handleTextureCompleteness(const char* functionName, bool prepareToDraw)
 {
     // All calling functions check isContextLost, so a duplicate check is not needed here.
     bool resetActiveUnit = false;
-    WebGLTexture::TextureExtensionFlag flag = static_cast<WebGLTexture::TextureExtensionFlag>((m_oesTextureFloatLinear ? WebGLTexture::TextureFloatLinearExtensionEnabled : 0)
-        | (m_oesTextureHalfFloatLinear ? WebGLTexture::TextureHalfFloatLinearExtensionEnabled : 0));
+    WebGLTexture::TextureExtensionFlag flag = static_cast<WebGLTexture::TextureExtensionFlag>((extensionEnabled(OESTextureFloatLinearName) ? WebGLTexture::TextureFloatLinearExtensionEnabled : 0)
+        | (extensionEnabled(OESTextureHalfFloatLinearName) ? WebGLTexture::TextureHalfFloatLinearExtensionEnabled : 0));
     for (unsigned ii = 0; ii < m_onePlusMaxNonDefaultTextureUnit; ++ii) {
         if ((m_textureUnits[ii].m_texture2DBinding.get() && m_textureUnits[ii].m_texture2DBinding->needToUseBlackTexture(flag))
             || (m_textureUnits[ii].m_textureCubeMapBinding.get() && m_textureUnits[ii].m_textureCubeMapBinding->needToUseBlackTexture(flag))) {
             if (ii != m_activeTextureUnit) {
                 m_context->activeTexture(ii);
                 resetActiveUnit = true;
             } else if (resetActiveUnit) {
                 m_context->activeTexture(ii);
                 resetActiveUnit = false;
             }
@@ skipping 13 matching lines @@
             if (m_textureUnits[ii].m_texture2DBinding && m_textureUnits[ii].m_texture2DBinding->needToUseBlackTexture(flag))
                 m_context->bindTexture(GL_TEXTURE_2D, objectOrZero(tex2D));
             if (m_textureUnits[ii].m_textureCubeMapBinding && m_textureUnits[ii].m_textureCubeMapBinding->needToUseBlackTexture(flag))
                 m_context->bindTexture(GL_TEXTURE_CUBE_MAP, objectOrZero(texCubeMap));
         }
     }
     if (resetActiveUnit)
         m_context->activeTexture(m_activeTextureUnit);
 }
 
-void WebGLRenderingContext::createFallbackBlackTextures1x1()
+void WebGLRenderingContextBase::createFallbackBlackTextures1x1()
 {
     // All calling functions check isContextLost, so a duplicate check is not needed here.
     unsigned char black[] = {0, 0, 0, 255};
     m_blackTexture2D = createTexture();
     m_context->bindTexture(GL_TEXTURE_2D, m_blackTexture2D->object());
     m_context->texImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1,
         0, GL_RGBA, GL_UNSIGNED_BYTE, black);
     m_context->bindTexture(GL_TEXTURE_2D, 0);
     m_blackTextureCubeMap = createTexture();
     m_context->bindTexture(GL_TEXTURE_CUBE_MAP, m_blackTextureCubeMap->object());
     m_context->texImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X, 0, GL_RGBA, 1, 1,
         0, GL_RGBA, GL_UNSIGNED_BYTE, black);
     m_context->texImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_X, 0, GL_RGBA, 1, 1,
         0, GL_RGBA, GL_UNSIGNED_BYTE, black);
     m_context->texImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_Y, 0, GL_RGBA, 1, 1,
         0, GL_RGBA, GL_UNSIGNED_BYTE, black);
     m_context->texImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, 0, GL_RGBA, 1, 1,
         0, GL_RGBA, GL_UNSIGNED_BYTE, black);
     m_context->texImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_Z, 0, GL_RGBA, 1, 1,
         0, GL_RGBA, GL_UNSIGNED_BYTE, black);
     m_context->texImage2D(GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, 0, GL_RGBA, 1, 1,
         0, GL_RGBA, GL_UNSIGNED_BYTE, black);
     m_context->bindTexture(GL_TEXTURE_CUBE_MAP, 0);
 }
 
-bool WebGLRenderingContext::isTexInternalFormatColorBufferCombinationValid(GLenum texInternalFormat, GLenum colorBufferFormat)
+bool WebGLRenderingContextBase::isTexInternalFormatColorBufferCombinationValid(GLenum texInternalFormat, GLenum colorBufferFormat)
 {
     unsigned need = WebGLImageConversion::getChannelBitsByFormat(texInternalFormat);
     unsigned have = WebGLImageConversion::getChannelBitsByFormat(colorBufferFormat);
     return (need & have) == need;
 }
 
-GLenum WebGLRenderingContext::boundFramebufferColorFormat()
+GLenum WebGLRenderingContextBase::boundFramebufferColorFormat()
 {
     if (m_framebufferBinding && m_framebufferBinding->object())
         return m_framebufferBinding->colorBufferFormat();
     if (m_requestedAttributes->alpha())
         return GL_RGBA;
     return GL_RGB;
 }
 
-WebGLTexture* WebGLRenderingContext::validateTextureBinding(const char* functionName, GLenum target, bool useSixEnumsForCubeMap)
+WebGLTexture* WebGLRenderingContextBase::validateTextureBinding(const char* functionName, GLenum target, bool useSixEnumsForCubeMap)
 {
     WebGLTexture* tex = 0;
     switch (target) {
     case GL_TEXTURE_2D:
         tex = m_textureUnits[m_activeTextureUnit].m_texture2DBinding.get();
         break;
     case GL_TEXTURE_CUBE_MAP_POSITIVE_X:
     case GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
     case GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
     case GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
@@ skipping 14 matching lines @@
         break;
     default:
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid texture target");
         return 0;
     }
     if (!tex)
         synthesizeGLError(GL_INVALID_OPERATION, functionName, "no texture");
     return tex;
 }
 
-bool WebGLRenderingContext::validateLocationLength(const char* functionName, const String& string)
+bool WebGLRenderingContextBase::validateLocationLength(const char* functionName, const String& string)
 {
     const unsigned maxWebGLLocationLength = 256;
     if (string.length() > maxWebGLLocationLength) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "location length > 256");
         return false;
     }
     return true;
 }
 
-bool WebGLRenderingContext::validateSize(const char* functionName, GLint x, GLint y)
+bool WebGLRenderingContextBase::validateSize(const char* functionName, GLint x, GLint y)
 {
     if (x < 0 || y < 0) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "size < 0");
         return false;
     }
     return true;
 }
 
-bool WebGLRenderingContext::validateString(const char* functionName, const String& string)
+bool WebGLRenderingContextBase::validateString(const char* functionName, const String& string)
 {
     for (size_t i = 0; i < string.length(); ++i) {
         if (!validateCharacter(string[i])) {
             synthesizeGLError(GL_INVALID_VALUE, functionName, "string not ASCII");
             return false;
         }
     }
     return true;
 }
 
-bool WebGLRenderingContext::validateTexFuncFormatAndType(const char* functionName, GLenum format, GLenum type, GLint level)
+bool WebGLRenderingContextBase::validateTexFuncFormatAndType(const char* functionName, GLenum format, GLenum type, GLint level)
 {
     switch (format) {
     case GL_ALPHA:
     case GL_LUMINANCE:
     case GL_LUMINANCE_ALPHA:
     case GL_RGB:
     case GL_RGBA:
         break;
     case GL_DEPTH_STENCIL_OES:
     case GL_DEPTH_COMPONENT:
-        if (m_webglDepthTexture)
+        if (extensionEnabled(WebGLDepthTextureName))
             break;
         synthesizeGLError(GL_INVALID_ENUM, functionName, "depth texture formats not enabled");
         return false;
     default:
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid texture format");
         return false;
     }
 
     switch (type) {
     case GL_UNSIGNED_BYTE:
     case GL_UNSIGNED_SHORT_5_6_5:
     case GL_UNSIGNED_SHORT_4_4_4_4:
     case GL_UNSIGNED_SHORT_5_5_5_1:
         break;
     case GL_FLOAT:
-        if (m_oesTextureFloat)
+        if (extensionEnabled(OESTextureFloatName))
             break;
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid texture type");
         return false;
     case GL_HALF_FLOAT_OES:
-        if (m_oesTextureHalfFloat)
+        if (extensionEnabled(OESTextureHalfFloatName))
             break;
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid texture type");
         return false;
     case GL_UNSIGNED_INT:
     case GL_UNSIGNED_INT_24_8_OES:
     case GL_UNSIGNED_SHORT:
-        if (m_webglDepthTexture)
+        if (extensionEnabled(WebGLDepthTextureName))
             break;
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid texture type");
         return false;
     default:
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid texture type");
         return false;
     }
 
     // Verify that the combination of format and type is supported.
     switch (format) {
@@ skipping 20 matching lines @@
         if (type != GL_UNSIGNED_BYTE
             && type != GL_UNSIGNED_SHORT_4_4_4_4
             && type != GL_UNSIGNED_SHORT_5_5_5_1
             && type != GL_FLOAT
             && type != GL_HALF_FLOAT_OES) {
             synthesizeGLError(GL_INVALID_OPERATION, functionName, "invalid type for RGBA format");
             return false;
         }
         break;
     case GL_DEPTH_COMPONENT:
-        if (!m_webglDepthTexture) {
+        if (!extensionEnabled(WebGLDepthTextureName)) {
             synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid format. DEPTH_COMPONENT not enabled");
             return false;
         }
         if (type != GL_UNSIGNED_SHORT
             && type != GL_UNSIGNED_INT) {
             synthesizeGLError(GL_INVALID_OPERATION, functionName, "invalid type for DEPTH_COMPONENT format");
             return false;
         }
         if (level > 0) {
             synthesizeGLError(GL_INVALID_OPERATION, functionName, "level must be 0 for DEPTH_COMPONENT format");
             return false;
         }
         break;
     case GL_DEPTH_STENCIL_OES:
-        if (!m_webglDepthTexture) {
+        if (!extensionEnabled(WebGLDepthTextureName)) {
             synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid format. DEPTH_STENCIL not enabled");
             return false;
         }
         if (type != GL_UNSIGNED_INT_24_8_OES) {
             synthesizeGLError(GL_INVALID_OPERATION, functionName, "invalid type for DEPTH_STENCIL format");
             return false;
         }
         if (level > 0) {
             synthesizeGLError(GL_INVALID_OPERATION, functionName, "level must be 0 for DEPTH_STENCIL format");
             return false;
         }
         break;
     default:
         ASSERT_NOT_REACHED();
     }
 
     return true;
 }
 
-bool WebGLRenderingContext::validateTexFuncLevel(const char* functionName, GLenum target, GLint level)
+bool WebGLRenderingContextBase::validateTexFuncLevel(const char* functionName, GLenum target, GLint level)
 {
     if (level < 0) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "level < 0");
         return false;
     }
     switch (target) {
     case GL_TEXTURE_2D:
         if (level >= m_maxTextureLevel) {
             synthesizeGLError(GL_INVALID_VALUE, functionName, "level out of range");
             return false;
         }
         break;
     case GL_TEXTURE_CUBE_MAP_POSITIVE_X:
     case GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
     case GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
     case GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
     case GL_TEXTURE_CUBE_MAP_POSITIVE_Z:
     case GL_TEXTURE_CUBE_MAP_NEGATIVE_Z:
         if (level >= m_maxCubeMapTextureLevel) {
             synthesizeGLError(GL_INVALID_VALUE, functionName, "level out of range");
             return false;
         }
         break;
     }
     // This function only checks if level is legal, so we return true and don't
     // generate INVALID_ENUM if target is illegal.
     return true;
 }
 
-bool WebGLRenderingContext::validateTexFuncDimensions(const char* functionName, TexFuncValidationFunctionType functionType,
+bool WebGLRenderingContextBase::validateTexFuncDimensions(const char* functionName, TexFuncValidationFunctionType functionType,
     GLenum target, GLint level, GLsizei width, GLsizei height)
 {
     if (width < 0 || height < 0) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "width or height < 0");
         return false;
     }
 
     switch (target) {
     case GL_TEXTURE_2D:
         if (width > (m_maxTextureSize >> level) || height > (m_maxTextureSize >> level)) {
@@ skipping 18 matching lines @@
             return false;
         }
         break;
     default:
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid target");
         return false;
     }
     return true;
 }
 
-bool WebGLRenderingContext::validateTexFuncParameters(const char* functionName, TexFuncValidationFunctionType functionType, GLenum target,
+bool WebGLRenderingContextBase::validateTexFuncParameters(const char* functionName, TexFuncValidationFunctionType functionType, GLenum target,
     GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type)
 {
     // We absolutely have to validate the format and type combination.
     // The texImage2D entry points taking HTMLImage, etc. will produce
     // temporary data based on this combination, so it must be legal.
     if (!validateTexFuncFormatAndType(functionName, format, type, level) || !validateTexFuncLevel(functionName, target, level))
         return false;
 
     if (!validateTexFuncDimensions(functionName, functionType, target, level, width, height))
         return false;
 
     if (format != internalformat) {
         synthesizeGLError(GL_INVALID_OPERATION, functionName, "format != internalformat");
         return false;
     }
 
     if (border) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "border != 0");
         return false;
     }
 
     return true;
 }
 
-bool WebGLRenderingContext::validateTexFuncData(const char* functionName, GLint level, GLsizei width, GLsizei height, GLenum format, GLenum type, ArrayBufferView* pixels, NullDisposition disposition)
+bool WebGLRenderingContextBase::validateTexFuncData(const char* functionName, GLint level, GLsizei width, GLsizei height, GLenum format, GLenum type, ArrayBufferView* pixels, NullDisposition disposition)
 {
     // All calling functions check isContextLost, so a duplicate check is not needed here.
     if (!pixels) {
         if (disposition == NullAllowed)
             return true;
         synthesizeGLError(GL_INVALID_VALUE, functionName, "no pixels");
         return false;
     }
 
     if (!validateTexFuncFormatAndType(functionName, format, type, level))
@@ skipping 47 matching lines @@
                 synthesizeGLError(GL_INVALID_OPERATION, functionName, "ArrayBufferView not big enough for request with UNPACK_ALIGNMENT > 1");
                 return false;
             }
         }
         synthesizeGLError(GL_INVALID_OPERATION, functionName, "ArrayBufferView not big enough for request");
         return false;
     }
     return true;
 }
 
-bool WebGLRenderingContext::validateCompressedTexFormat(GLenum format)
+bool WebGLRenderingContextBase::validateCompressedTexFormat(GLenum format)
 {
     return m_compressedTextureFormats.contains(format);
 }
 
-bool WebGLRenderingContext::validateCompressedTexFuncData(const char* functionName, GLsizei width, GLsizei height, GLenum format, ArrayBufferView* pixels)
+bool WebGLRenderingContextBase::validateCompressedTexFuncData(const char* functionName, GLsizei width, GLsizei height, GLenum format, ArrayBufferView* pixels)
 {
     if (!pixels) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "no pixels");
         return false;
     }
     if (width < 0 || height < 0) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "width or height < 0");
         return false;
     }
 
@@ skipping 53 matching lines @@
     }
 
     if (pixels->byteLength() != bytesRequired) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "length of ArrayBufferView is not correct for dimensions");
         return false;
     }
 
     return true;
 }
 
-bool WebGLRenderingContext::validateCompressedTexDimensions(const char* functionName, TexFuncValidationFunctionType functionType, GLenum target, GLint level, GLsizei width, GLsizei height, GLenum format)
+bool WebGLRenderingContextBase::validateCompressedTexDimensions(const char* functionName, TexFuncValidationFunctionType functionType, GLenum target, GLint level, GLsizei width, GLsizei height, GLenum format)
 {
     if (!validateTexFuncDimensions(functionName, functionType, target, level, width, height))
         return false;
 
     switch (format) {
     case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
     case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
     case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
     case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT: {
         const int kBlockWidth = 4;
         const int kBlockHeight = 4;
         bool widthValid = (level && width == 1) || (level && width == 2) || !(width % kBlockWidth);
         bool heightValid = (level && height == 1) || (level && height == 2) || !(height % kBlockHeight);
         if (!widthValid || !heightValid) {
             synthesizeGLError(GL_INVALID_OPERATION, functionName, "width or height invalid for level");
             return false;
         }
         return true;
     }
     default:
         return false;
     }
 }
 
-bool WebGLRenderingContext::validateCompressedTexSubDimensions(const char* functionName, GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, WebGLTexture* tex)
+bool WebGLRenderingContextBase::validateCompressedTexSubDimensions(const char* functionName, GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, WebGLTexture* tex)
 {
     if (xoffset < 0 || yoffset < 0) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "xoffset or yoffset < 0");
         return false;
     }
 
     switch (format) {
     case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
     case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
     case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
     case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT: {
         const int kBlockWidth = 4;
         const int kBlockHeight = 4;
         if ((xoffset % kBlockWidth) || (yoffset % kBlockHeight)) {
             synthesizeGLError(GL_INVALID_OPERATION, functionName, "xoffset or yoffset not multiple of 4");
             return false;
         }
         if (width - xoffset > tex->getWidth(target, level)
             || height - yoffset > tex->getHeight(target, level)) {
             synthesizeGLError(GL_INVALID_OPERATION, functionName, "dimensions out of range");
             return false;
         }
         return validateCompressedTexDimensions(functionName, TexSubImage2D, target, level, width, height, format);
     }
     default:
         return false;
     }
 }
 
-bool WebGLRenderingContext::validateDrawMode(const char* functionName, GLenum mode)
+bool WebGLRenderingContextBase::validateDrawMode(const char* functionName, GLenum mode)
 {
     switch (mode) {
     case GL_POINTS:
     case GL_LINE_STRIP:
     case GL_LINE_LOOP:
     case GL_LINES:
     case GL_TRIANGLE_STRIP:
     case GL_TRIANGLE_FAN:
     case GL_TRIANGLES:
         return true;
     default:
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid draw mode");
         return false;
     }
 }
 
-bool WebGLRenderingContext::validateStencilSettings(const char* functionName)
+bool WebGLRenderingContextBase::validateStencilSettings(const char* functionName)
 {
     if (m_stencilMask != m_stencilMaskBack || m_stencilFuncRef != m_stencilFuncRefBack || m_stencilFuncMask != m_stencilFuncMaskBack) {
         synthesizeGLError(GL_INVALID_OPERATION, functionName, "front and back stencils settings do not match");
         return false;
     }
     return true;
 }
 
-bool WebGLRenderingContext::validateStencilOrDepthFunc(const char* functionName, GLenum func)
+bool WebGLRenderingContextBase::validateStencilOrDepthFunc(const char* functionName, GLenum func)
 {
     switch (func) {
     case GL_NEVER:
     case GL_LESS:
     case GL_LEQUAL:
     case GL_GREATER:
     case GL_GEQUAL:
     case GL_EQUAL:
     case GL_NOTEQUAL:
     case GL_ALWAYS:
         return true;
     default:
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid function");
         return false;
     }
 }
 
-void WebGLRenderingContext::printGLErrorToConsole(const String& message)
+void WebGLRenderingContextBase::printGLErrorToConsole(const String& message)
 {
     if (!m_numGLErrorsToConsoleAllowed)
         return;
 
     --m_numGLErrorsToConsoleAllowed;
     printWarningToConsole(message);
 
     if (!m_numGLErrorsToConsoleAllowed)
         printWarningToConsole("WebGL: too many errors, no more errors will be reported to the console for this context.");
 
     return;
 }
 
-void WebGLRenderingContext::printWarningToConsole(const String& message)
+void WebGLRenderingContextBase::printWarningToConsole(const String& message)
 {
     if (!canvas())
         return;
     canvas()->document().addConsoleMessage(RenderingMessageSource, WarningMessageLevel, message);
 }
 
-bool WebGLRenderingContext::validateFramebufferFuncParameters(const char* functionName, GLenum target, GLenum attachment)
+bool WebGLRenderingContextBase::validateFramebufferFuncParameters(const char* functionName, GLenum target, GLenum attachment)
 {
     if (target != GL_FRAMEBUFFER) {
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid target");
         return false;
     }
     switch (attachment) {
     case GL_COLOR_ATTACHMENT0:
     case GL_DEPTH_ATTACHMENT:
     case GL_STENCIL_ATTACHMENT:
     case GC3D_DEPTH_STENCIL_ATTACHMENT_WEBGL:
         break;
     default:
-        if (m_webglDrawBuffers
+        if (extensionEnabled(WebGLDrawBuffersName)
             && attachment > GL_COLOR_ATTACHMENT0
             && attachment < static_cast<GLenum>(GL_COLOR_ATTACHMENT0 + maxColorAttachments()))
             break;
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid attachment");
         return false;
     }
     return true;
 }
 
-bool WebGLRenderingContext::validateBlendEquation(const char* functionName, GLenum mode)
+bool WebGLRenderingContextBase::validateBlendEquation(const char* functionName, GLenum mode)
 {
     switch (mode) {
     case GL_FUNC_ADD:
     case GL_FUNC_SUBTRACT:
     case GL_FUNC_REVERSE_SUBTRACT:
         return true;
     default:
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid mode");
         return false;
     }
 }
 
-bool WebGLRenderingContext::validateBlendFuncFactors(const char* functionName, GLenum src, GLenum dst)
+bool WebGLRenderingContextBase::validateBlendFuncFactors(const char* functionName, GLenum src, GLenum dst)
 {
     if (((src == GL_CONSTANT_COLOR || src == GL_ONE_MINUS_CONSTANT_COLOR)
         && (dst == GL_CONSTANT_ALPHA || dst == GL_ONE_MINUS_CONSTANT_ALPHA))
         || ((dst == GL_CONSTANT_COLOR || dst == GL_ONE_MINUS_CONSTANT_COLOR)
         && (src == GL_CONSTANT_ALPHA || src == GL_ONE_MINUS_CONSTANT_ALPHA))) {
         synthesizeGLError(GL_INVALID_OPERATION, functionName, "incompatible src and dst");
         return false;
     }
     return true;
 }
 
-bool WebGLRenderingContext::validateCapability(const char* functionName, GLenum cap)
+bool WebGLRenderingContextBase::validateCapability(const char* functionName, GLenum cap)
 {
     switch (cap) {
     case GL_BLEND:
     case GL_CULL_FACE:
     case GL_DEPTH_TEST:
     case GL_DITHER:
     case GL_POLYGON_OFFSET_FILL:
     case GL_SAMPLE_ALPHA_TO_COVERAGE:
     case GL_SAMPLE_COVERAGE:
     case GL_SCISSOR_TEST:
     case GL_STENCIL_TEST:
         return true;
     default:
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid capability");
         return false;
     }
 }
 
-bool WebGLRenderingContext::validateUniformParameters(const char* functionName, const WebGLUniformLocation* location, Float32Array* v, GLsizei requiredMinSize)
+bool WebGLRenderingContextBase::validateUniformParameters(const char* functionName, const WebGLUniformLocation* location, Float32Array* v, GLsizei requiredMinSize)
 {
     if (!v) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "no array");
         return false;
     }
     return validateUniformMatrixParameters(functionName, location, false, v->data(), v->length(), requiredMinSize);
 }
 
-bool WebGLRenderingContext::validateUniformParameters(const char* functionName, const WebGLUniformLocation* location, Int32Array* v, GLsizei requiredMinSize)
+bool WebGLRenderingContextBase::validateUniformParameters(const char* functionName, const WebGLUniformLocation* location, Int32Array* v, GLsizei requiredMinSize)
 {
     if (!v) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "no array");
         return false;
     }
     return validateUniformMatrixParameters(functionName, location, false, v->data(), v->length(), requiredMinSize);
 }
 
-bool WebGLRenderingContext::validateUniformParameters(const char* functionName, const WebGLUniformLocation* location, void* v, GLsizei size, GLsizei requiredMinSize)
+bool WebGLRenderingContextBase::validateUniformParameters(const char* functionName, const WebGLUniformLocation* location, void* v, GLsizei size, GLsizei requiredMinSize)
 {
     return validateUniformMatrixParameters(functionName, location, false, v, size, requiredMinSize);
 }
 
-bool WebGLRenderingContext::validateUniformMatrixParameters(const char* functionName, const WebGLUniformLocation* location, GLboolean transpose, Float32Array* v, GLsizei requiredMinSize)
+bool WebGLRenderingContextBase::validateUniformMatrixParameters(const char* functionName, const WebGLUniformLocation* location, GLboolean transpose, Float32Array* v, GLsizei requiredMinSize)
 {
     if (!v) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "no array");
         return false;
     }
     return validateUniformMatrixParameters(functionName, location, transpose, v->data(), v->length(), requiredMinSize);
 }
 
-bool WebGLRenderingContext::validateUniformMatrixParameters(const char* functionName, const WebGLUniformLocation* location, GLboolean transpose, void* v, GLsizei size, GLsizei requiredMinSize)
+bool WebGLRenderingContextBase::validateUniformMatrixParameters(const char* functionName, const WebGLUniformLocation* location, GLboolean transpose, void* v, GLsizei size, GLsizei requiredMinSize)
 {
     if (!location)
         return false;
     if (location->program() != m_currentProgram) {
         synthesizeGLError(GL_INVALID_OPERATION, functionName, "location is not from current program");
         return false;
     }
     if (!v) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "no array");
         return false;
     }
     if (transpose) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "transpose not FALSE");
         return false;
     }
     if (size < requiredMinSize || (size % requiredMinSize)) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "invalid size");
         return false;
     }
     return true;
 }
 
-WebGLBuffer* WebGLRenderingContext::validateBufferDataParameters(const char* functionName, GLenum target, GLenum usage)
+WebGLBuffer* WebGLRenderingContextBase::validateBufferDataParameters(const char* functionName, GLenum target, GLenum usage)
 {
     WebGLBuffer* buffer = 0;
     switch (target) {
     case GL_ELEMENT_ARRAY_BUFFER:
         buffer = m_boundVertexArrayObject->boundElementArrayBuffer().get();
         break;
     case GL_ARRAY_BUFFER:
         buffer = m_boundArrayBuffer.get();
         break;
     default:
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid target");
         return 0;
     }
     if (!buffer) {
         synthesizeGLError(GL_INVALID_OPERATION, functionName, "no buffer");
         return 0;
     }
     switch (usage) {
     case GL_STREAM_DRAW:
     case GL_STATIC_DRAW:
     case GL_DYNAMIC_DRAW:
         return buffer;
     }
     synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid usage");
     return 0;
 }
 
-bool WebGLRenderingContext::validateHTMLImageElement(const char* functionName, HTMLImageElement* image, ExceptionState& exceptionState)
+bool WebGLRenderingContextBase::validateHTMLImageElement(const char* functionName, HTMLImageElement* image, ExceptionState& exceptionState)
 {
     if (!image || !image->cachedImage()) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "no image");
         return false;
     }
     const KURL& url = image->cachedImage()->response().url();
     if (url.isNull() || url.isEmpty() || !url.isValid()) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "invalid image");
         return false;
     }
     if (wouldTaintOrigin(image)) {
         exceptionState.throwSecurityError("The cross-origin image at " + url.elidedString() + " may not be loaded.");
         return false;
     }
     return true;
 }
 
-bool WebGLRenderingContext::validateHTMLCanvasElement(const char* functionName, HTMLCanvasElement* canvas, ExceptionState& exceptionState)
+bool WebGLRenderingContextBase::validateHTMLCanvasElement(const char* functionName, HTMLCanvasElement* canvas, ExceptionState& exceptionState)
 {
     if (!canvas || !canvas->buffer()) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "no canvas");
         return false;
     }
     if (wouldTaintOrigin(canvas)) {
         exceptionState.throwSecurityError("Tainted canvases may not be loaded.");
         return false;
     }
     return true;
 }
 
-bool WebGLRenderingContext::validateHTMLVideoElement(const char* functionName, HTMLVideoElement* video, ExceptionState& exceptionState)
+bool WebGLRenderingContextBase::validateHTMLVideoElement(const char* functionName, HTMLVideoElement* video, ExceptionState& exceptionState)
 {
     if (!video || !video->videoWidth() || !video->videoHeight()) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "no video");
         return false;
     }
     if (wouldTaintOrigin(video)) {
         exceptionState.throwSecurityError("The video element contains cross-origin data, and may not be loaded.");
         return false;
     }
     return true;
 }
 
-bool WebGLRenderingContext::validateDrawArrays(const char* functionName, GLenum mode, GLint first, GLsizei count)
+bool WebGLRenderingContextBase::validateDrawArrays(const char* functionName, GLenum mode, GLint first, GLsizei count)
 {
     if (isContextLost() || !validateDrawMode(functionName, mode))
         return false;
 
     if (!validateStencilSettings(functionName))
         return false;
 
     if (first < 0 || count < 0) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "first or count < 0");
         return false;
@@ skipping 10 matching lines @@
 
     const char* reason = "framebuffer incomplete";
     if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context.get(), &reason)) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, functionName, reason);
         return false;
     }
 
     return true;
 }
 
-bool WebGLRenderingContext::validateDrawElements(const char* functionName, GLenum mode, GLsizei count, GLenum type, long long offset)
+bool WebGLRenderingContextBase::validateDrawElements(const char* functionName, GLenum mode, GLsizei count, GLenum type, long long offset)
 {
     if (isContextLost() || !validateDrawMode(functionName, mode))
         return false;
 
     if (!validateStencilSettings(functionName))
         return false;
 
     switch (type) {
     case GL_UNSIGNED_BYTE:
     case GL_UNSIGNED_SHORT:
         break;
     case GL_UNSIGNED_INT:
-        if (m_oesElementIndexUint)
+        if (extensionEnabled(OESElementIndexUintName))
             break;
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid type");
         return false;
     default:
         synthesizeGLError(GL_INVALID_ENUM, functionName, "invalid type");
         return false;
     }
 
     if (count < 0 || offset < 0) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "count or offset < 0");
@@ skipping 17 matching lines @@
     const char* reason = "framebuffer incomplete";
     if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context.get(), &reason)) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, functionName, reason);
         return false;
     }
 
     return true;
 }
 
 // Helper function to validate draw*Instanced calls
-bool WebGLRenderingContext::validateDrawInstanced(const char* functionName, GLsizei primcount)
+bool WebGLRenderingContextBase::validateDrawInstanced(const char* functionName, GLsizei primcount)
 {
     if (primcount < 0) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "primcount < 0");
         return false;
     }
 
     // Ensure at least one enabled vertex attrib has a divisor of 0.
     for (unsigned i = 0; i < m_onePlusMaxEnabledAttribIndex; ++i) {
         const WebGLVertexArrayObjectOES::VertexAttribState& state = m_boundVertexArrayObject->getVertexAttribState(i);
         if (state.enabled && !state.divisor)
             return true;
     }
 
     synthesizeGLError(GL_INVALID_OPERATION, functionName, "at least one enabled attribute must have a divisor of 0");
     return false;
 }
 
-void WebGLRenderingContext::vertexAttribfImpl(const char* functionName, GLuint index, GLsizei expectedSize, GLfloat v0, GLfloat v1, GLfloat v2, GLfloat v3)
+void WebGLRenderingContextBase::vertexAttribfImpl(const char* functionName, GLuint index, GLsizei expectedSize, GLfloat v0, GLfloat v1, GLfloat v2, GLfloat v3)
 {
     if (isContextLost())
         return;
     if (index >= m_maxVertexAttribs) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "index out of range");
         return;
     }
     // In GL, we skip setting vertexAttrib0 values.
     switch (expectedSize) {
     case 1:
         m_context->vertexAttrib1f(index, v0);
         break;
     case 2:
         m_context->vertexAttrib2f(index, v0, v1);
         break;
     case 3:
         m_context->vertexAttrib3f(index, v0, v1, v2);
         break;
     case 4:
         m_context->vertexAttrib4f(index, v0, v1, v2, v3);
         break;
     }
     VertexAttribValue& attribValue = m_vertexAttribValue[index];
     attribValue.value[0] = v0;
     attribValue.value[1] = v1;
     attribValue.value[2] = v2;
     attribValue.value[3] = v3;
 }
 
-void WebGLRenderingContext::vertexAttribfvImpl(const char* functionName, GLuint index, Float32Array* v, GLsizei expectedSize)
+void WebGLRenderingContextBase::vertexAttribfvImpl(const char* functionName, GLuint index, Float32Array* v, GLsizei expectedSize)
 {
     if (isContextLost())
         return;
     if (!v) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "no array");
         return;
     }
     vertexAttribfvImpl(functionName, index, v->data(), v->length(), expectedSize);
 }
 
-void WebGLRenderingContext::vertexAttribfvImpl(const char* functionName, GLuint index, GLfloat* v, GLsizei size, GLsizei expectedSize)
+void WebGLRenderingContextBase::vertexAttribfvImpl(const char* functionName, GLuint index, GLfloat* v, GLsizei size, GLsizei expectedSize)
 {
     if (isContextLost())
         return;
     if (!v) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "no array");
         return;
     }
     if (size < expectedSize) {
         synthesizeGLError(GL_INVALID_VALUE, functionName, "invalid size");
         return;
@@ skipping 16 matching lines @@
     case 4:
         m_context->vertexAttrib4fv(index, v);
         break;
     }
     VertexAttribValue& attribValue = m_vertexAttribValue[index];
     attribValue.initValue();
     for (int ii = 0; ii < expectedSize; ++ii)
         attribValue.value[ii] = v[ii];
 }
 
-void WebGLRenderingContext::dispatchContextLostEvent(Timer<WebGLRenderingContext>*)
+void WebGLRenderingContextBase::dispatchContextLostEvent(Timer<WebGLRenderingContextBase>*)
 {
     RefPtr<WebGLContextEvent> event = WebGLContextEvent::create(EventTypeNames::webglcontextlost, false, true, "");
     canvas()->dispatchEvent(event);
     m_restoreAllowed = event->defaultPrevented();
     deactivateContext(this, m_contextLostMode != RealLostContext && m_restoreAllowed);
     if ((m_contextLostMode == RealLostContext || m_contextLostMode == AutoRecoverSyntheticLostContext) && m_restoreAllowed)
         m_restoreTimer.startOneShot(0);
 }
 
-void WebGLRenderingContext::maybeRestoreContext(Timer<WebGLRenderingContext>*)
+void WebGLRenderingContextBase::maybeRestoreContext(Timer<WebGLRenderingContextBase>*)
 {
     ASSERT(isContextLost());
 
     // The rendering context is not restored unless the default behavior of the
     // webglcontextlost event was prevented earlier.
     //
     // Because of the way m_restoreTimer is set up for real vs. synthetic lost
     // context events, we don't have to worry about this test short-circuiting
     // the retry loop for real context lost events.
     if (!m_restoreAllowed)
@@ skipping 35 matching lines @@
     m_lostContextErrors.clear();
 
     m_context = context.release();
     m_contextLost = false;
 
     setupFlags();
     initializeNewContext();
     canvas()->dispatchEvent(WebGLContextEvent::create(EventTypeNames::webglcontextrestored, false, true, ""));
 }
 
-String WebGLRenderingContext::ensureNotNull(const String& text) const
+String WebGLRenderingContextBase::ensureNotNull(const String& text) const
 {
     if (text.isNull())
         return WTF::emptyString();
     return text;
 }
 
-WebGLRenderingContext::LRUImageBufferCache::LRUImageBufferCache(int capacity)
+WebGLRenderingContextBase::LRUImageBufferCache::LRUImageBufferCache(int capacity)
     : m_buffers(adoptArrayPtr(new OwnPtr<ImageBuffer>[capacity]))
     , m_capacity(capacity)
 {
 }
 
-ImageBuffer* WebGLRenderingContext::LRUImageBufferCache::imageBuffer(const IntSize& size)
+ImageBuffer* WebGLRenderingContextBase::LRUImageBufferCache::imageBuffer(const IntSize& size)
 {
     int i;
     for (i = 0; i < m_capacity; ++i) {
         ImageBuffer* buf = m_buffers[i].get();
         if (!buf)
             break;
         if (buf->size() != size)
             continue;
         bubbleToFront(i);
         return buf;
     }
 
     OwnPtr<ImageBuffer> temp(ImageBuffer::create(size));
     if (!temp)
         return 0;
     i = std::min(m_capacity - 1, i);
     m_buffers[i] = temp.release();
 
     ImageBuffer* buf = m_buffers[i].get();
     bubbleToFront(i);
     return buf;
 }
 
-void WebGLRenderingContext::LRUImageBufferCache::bubbleToFront(int idx)
+void WebGLRenderingContextBase::LRUImageBufferCache::bubbleToFront(int idx)
 {
     for (int i = idx; i > 0; --i)
         m_buffers[i].swap(m_buffers[i-1]);
 }
 
 namespace {
 
     String GetErrorString(GLenum error)
     {
         switch (error) {
         case GL_INVALID_ENUM:
             return "INVALID_ENUM";
         case GL_INVALID_VALUE:
             return "INVALID_VALUE";
         case GL_INVALID_OPERATION:
             return "INVALID_OPERATION";
         case GL_OUT_OF_MEMORY:
             return "OUT_OF_MEMORY";
         case GL_INVALID_FRAMEBUFFER_OPERATION:
             return "INVALID_FRAMEBUFFER_OPERATION";
         case GC3D_CONTEXT_LOST_WEBGL:
             return "CONTEXT_LOST_WEBGL";
         default:
             return String::format("WebGL ERROR(0x%04X)", error);
         }
     }
 
 } // namespace anonymous
 
-void WebGLRenderingContext::synthesizeGLError(GLenum error, const char* functionName, const char* description, ConsoleDisplayPreference display)
+void WebGLRenderingContextBase::synthesizeGLError(GLenum error, const char* functionName, const char* description, ConsoleDisplayPreference display)
 {
     String errorType = GetErrorString(error);
     if (m_synthesizedErrorsToConsole && display == DisplayInConsole) {
         String message = String("WebGL: ") + errorType +  ": " + String(functionName) + ": " + String(description);
         printGLErrorToConsole(message);
     }
     if (!isContextLost())
         m_context->synthesizeGLError(error);
     else {
         if (m_lostContextErrors.find(error) == WTF::kNotFound)
             m_lostContextErrors.append(error);
     }
     InspectorInstrumentation::didFireWebGLError(canvas(), errorType);
 }
 
-void WebGLRenderingContext::emitGLWarning(const char* functionName, const char* description)
+void WebGLRenderingContextBase::emitGLWarning(const char* functionName, const char* description)
 {
     if (m_synthesizedErrorsToConsole) {
         String message = String("WebGL: ") + String(functionName) + ": " + String(description);
         printGLErrorToConsole(message);
     }
     InspectorInstrumentation::didFireWebGLWarning(canvas());
 }
 
-void WebGLRenderingContext::applyStencilTest()
+void WebGLRenderingContextBase::applyStencilTest()
 {
     bool haveStencilBuffer = false;
 
     if (m_framebufferBinding)
         haveStencilBuffer = m_framebufferBinding->hasStencilBuffer();
     else {
         RefPtr<WebGLContextAttributes> attributes = getContextAttributes();
         haveStencilBuffer = attributes->stencil();
     }
     enableOrDisable(GL_STENCIL_TEST,
                     m_stencilEnabled && haveStencilBuffer);
 }
 
-void WebGLRenderingContext::enableOrDisable(GLenum capability, bool enable)
+void WebGLRenderingContextBase::enableOrDisable(GLenum capability, bool enable)
 {
     if (isContextLost())
         return;
     if (enable)
         m_context->enable(capability);
     else
         m_context->disable(capability);
 }
 
-IntSize WebGLRenderingContext::clampedCanvasSize()
+IntSize WebGLRenderingContextBase::clampedCanvasSize()
 {
     return IntSize(clamp(canvas()->width(), 1, m_maxViewportDims[0]),
                    clamp(canvas()->height(), 1, m_maxViewportDims[1]));
 }
 
-GLint WebGLRenderingContext::maxDrawBuffers()
+GLint WebGLRenderingContextBase::maxDrawBuffers()
 {
-    if (isContextLost() || !m_webglDrawBuffers)
+    if (isContextLost() || !extensionEnabled(WebGLDrawBuffersName))
         return 0;
     if (!m_maxDrawBuffers)
         m_context->getIntegerv(GL_MAX_DRAW_BUFFERS_EXT, &m_maxDrawBuffers);
     if (!m_maxColorAttachments)
         m_context->getIntegerv(GL_MAX_COLOR_ATTACHMENTS_EXT, &m_maxColorAttachments);
     // WEBGL_draw_buffers requires MAX_COLOR_ATTACHMENTS >= MAX_DRAW_BUFFERS.
     return std::min(m_maxDrawBuffers, m_maxColorAttachments);
 }
 
-GLint WebGLRenderingContext::maxColorAttachments()
+GLint WebGLRenderingContextBase::maxColorAttachments()
 {
-    if (isContextLost() || !m_webglDrawBuffers)
+    if (isContextLost() || !extensionEnabled(WebGLDrawBuffersName))
         return 0;
     if (!m_maxColorAttachments)
         m_context->getIntegerv(GL_MAX_COLOR_ATTACHMENTS_EXT, &m_maxColorAttachments);
     return m_maxColorAttachments;
 }
 
-void WebGLRenderingContext::setBackDrawBuffer(GLenum buf)
+void WebGLRenderingContextBase::setBackDrawBuffer(GLenum buf)
 {
     m_backDrawBuffer = buf;
 }
 
-void WebGLRenderingContext::restoreCurrentFramebuffer()
+void WebGLRenderingContextBase::restoreCurrentFramebuffer()
 {
     bindFramebuffer(GL_FRAMEBUFFER, m_framebufferBinding.get());
 }
 
-void WebGLRenderingContext::restoreCurrentTexture2D()
+void WebGLRenderingContextBase::restoreCurrentTexture2D()
 {
     bindTexture(GL_TEXTURE_2D, m_textureUnits[m_activeTextureUnit].m_texture2DBinding.get());
 }
 
-void WebGLRenderingContext::multisamplingChanged(bool enabled)
+void WebGLRenderingContextBase::multisamplingChanged(bool enabled)
 {
     if (m_multisamplingAllowed != enabled) {
         m_multisamplingAllowed = enabled;
-        forceLostContext(WebGLRenderingContext::AutoRecoverSyntheticLostContext);
+        forceLostContext(WebGLRenderingContextBase::AutoRecoverSyntheticLostContext);
     }
 }
 
-void WebGLRenderingContext::findNewMaxEnabledAttribIndex()
+void WebGLRenderingContextBase::findNewMaxEnabledAttribIndex()
 {
     // Trace backwards from the current max to find the new max enabled attrib index
     int startIndex = m_onePlusMaxEnabledAttribIndex - 1;
     for (int i = startIndex; i >= 0; --i) {
         if (m_boundVertexArrayObject->getVertexAttribState(i).enabled) {
             m_onePlusMaxEnabledAttribIndex = i + 1;
             return;
         }
     }
     m_onePlusMaxEnabledAttribIndex = 0;
 }
 
-void WebGLRenderingContext::findNewMaxNonDefaultTextureUnit()
+void WebGLRenderingContextBase::findNewMaxNonDefaultTextureUnit()
 {
     // Trace backwards from the current max to find the new max non-default texture unit
     int startIndex = m_onePlusMaxNonDefaultTextureUnit - 1;
     for (int i = startIndex; i >= 0; --i) {
         if (m_textureUnits[i].m_texture2DBinding
             || m_textureUnits[i].m_textureCubeMapBinding) {
             m_onePlusMaxNonDefaultTextureUnit = i + 1;
             return;
         }
     }
     m_onePlusMaxNonDefaultTextureUnit = 0;
 }
 
 } // namespace WebCore