WebGL: Transfer ownership of WebGraphicsContext3D from WebGLRenderingContext to DrawingBuffer.

Source/core/html/canvas/WebGLRenderingContext.cpp

Index: Source/core/html/canvas/WebGLRenderingContext.cpp
diff --git a/Source/core/html/canvas/WebGLRenderingContext.cpp b/Source/core/html/canvas/WebGLRenderingContext.cpp
index 444dd04a1d81629d1edbae5e7177348aac30cc29..ef10840f93aae4c2c4ddf64c04449dc3733e7ed3 100644
--- a/Source/core/html/canvas/WebGLRenderingContext.cpp
+++ b/Source/core/html/canvas/WebGLRenderingContext.cpp
@@ -515,7 +515,7 @@ PassOwnPtr<WebGLRenderingContext> WebGLRenderingContext::create(HTMLCanvasElemen
     OwnPtr<WebGLRenderingContext> renderingContext = adoptPtr(new WebGLRenderingContext(canvas, context.release(), attrs));
     renderingContext->suspendIfNeeded();
 
-    if (renderingContext->m_drawingBuffer->isZeroSized()) {
+    if (!renderingContext->m_drawingBuffer) {
         canvas->dispatchEvent(WebGLContextEvent::create(EventTypeNames::webglcontextcreationerror, false, true, "Could not create a WebGL context."));
         return nullptr;
     }
@@ -526,8 +526,8 @@ PassOwnPtr<WebGLRenderingContext> WebGLRenderingContext::create(HTMLCanvasElemen
 WebGLRenderingContext::WebGLRenderingContext(HTMLCanvasElement* passedCanvas, PassOwnPtr<blink::WebGraphicsContext3D> context, WebGLContextAttributes* requestedAttributes)
     : CanvasRenderingContext(passedCanvas)
     , ActiveDOMObject(&passedCanvas->document())
-    , m_context(context)
     , m_drawingBuffer(0)
+    , m_context(context.get())
     , m_dispatchContextLostEventTimer(this, &WebGLRenderingContext::dispatchContextLostEvent)
     , m_restoreAllowed(false)
     , m_restoreTimer(this, &WebGLRenderingContext::maybeRestoreContext)
@@ -555,13 +555,13 @@ WebGLRenderingContext::WebGLRenderingContext(HTMLCanvasElement* passedCanvas, Pa
 
     // 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());
+    m_drawingBuffer = DrawingBuffer::create(context, clampedCanvasSize(), preserve, contextEvictionManager.release());
+    if (!m_drawingBuffer)
+        return;
 
-    if (!m_drawingBuffer->isZeroSized()) {
-        m_drawingBuffer->bind();
-        setupFlags();
-        initializeNewContext();
-    }
+    m_drawingBuffer->bind();
+    setupFlags();
+    initializeNewContext();
 
     // Register extensions.
     static const char* const webkitPrefix[] = { "WEBKIT_", 0, };
@@ -655,8 +655,6 @@ void WebGLRenderingContext::initializeNewContext()
 
     createFallbackBlackTextures1x1();
 
-    m_drawingBuffer->reset(clampedCanvasSize());
-
     m_context->viewport(0, 0, drawingBufferWidth(), drawingBufferHeight());
     m_context->scissor(0, 0, drawingBufferWidth(), drawingBufferHeight());
 
@@ -757,17 +755,19 @@ void WebGLRenderingContext::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();
+    if (!m_context) {
+        ASSERT(!m_drawingBuffer);
+        return;
+    }
 
     m_extensionsUtil.clear();
 
-    if (m_context) {
-        m_context->setContextLostCallback(0);
-        m_context->setErrorMessageCallback(0);
-        m_context.clear();
-    }
+    m_context->setContextLostCallback(0);
+    m_context->setErrorMessageCallback(0);
+    m_context = 0;
+
+    ASSERT(m_drawingBuffer);
+    m_drawingBuffer.clear();
 }
 
 void WebGLRenderingContext::markContextChanged()
@@ -959,12 +959,12 @@ void WebGLRenderingContext::reshape(int width, int height)
 
 int WebGLRenderingContext::drawingBufferWidth() const
 {
-    return m_drawingBuffer->size().width();
+    return isContextLost() ? 0 : m_drawingBuffer->size().width();
 }
 
 int WebGLRenderingContext::drawingBufferHeight() const
 {
-    return m_drawingBuffer->size().height();
+    return isContextLost() ? 0 : m_drawingBuffer->size().height();
 }
 
 unsigned WebGLRenderingContext::sizeInBytes(GLenum type)
@@ -1312,7 +1312,7 @@ void WebGLRenderingContext::clear(GLbitfield mask)
         return;
     }
     const char* reason = "framebuffer incomplete";
-    if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context.get(), &reason)) {
+    if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context, &reason)) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, "clear", reason);
         return;
     }
@@ -1466,7 +1466,7 @@ void WebGLRenderingContext::copyTexImage2D(GLenum target, GLint level, GLenum in
         return;
     }
     const char* reason = "framebuffer incomplete";
-    if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context.get(), &reason)) {
+    if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context, &reason)) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, "copyTexImage2D", reason);
         return;
     }
@@ -1509,7 +1509,7 @@ void WebGLRenderingContext::copyTexSubImage2D(GLenum target, GLint level, GLint
         return;
     }
     const char* reason = "framebuffer incomplete";
-    if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context.get(), &reason)) {
+    if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context, &reason)) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, "copyTexSubImage2D", reason);
         return;
     }
@@ -1616,7 +1616,7 @@ bool WebGLRenderingContext::deleteObject(WebGLObject* object)
     if (object->object()) {
         // We need to pass in context here because we want
         // things in this context unbound.
-        object->deleteObject(m_context.get());
+        object->deleteObject(m_context);
     }
     return true;
 }
@@ -1729,7 +1729,7 @@ void WebGLRenderingContext::detachShader(WebGLProgram* program, WebGLShader* sha
         return;
     }
     m_context->detachShader(objectOrZero(program), objectOrZero(shader));
-    shader->onDetached(m_context.get());
+    shader->onDetached(m_context);
 }
 
 void WebGLRenderingContext::disable(GLenum cap)
@@ -2903,7 +2903,7 @@ GLboolean WebGLRenderingContext::isBuffer(WebGLBuffer* buffer)
     return m_context->isBuffer(buffer->object());
 }
 
-bool WebGLRenderingContext::isContextLost()
+bool WebGLRenderingContext::isContextLost() const
 {
     return m_contextLost;
 }
@@ -3070,7 +3070,7 @@ void WebGLRenderingContext::readPixels(GLint x, GLint y, GLsizei width, GLsizei
         return;
     }
     const char* reason = "framebuffer incomplete";
-    if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context.get(), &reason)) {
+    if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context, &reason)) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, "readPixels", reason);
         return;
     }
@@ -3134,7 +3134,7 @@ void WebGLRenderingContext::renderbufferStorage(GLenum target, GLenum internalfo
         m_context->renderbufferStorage(target, internalformat, width, height);
         m_renderbufferBinding->setInternalFormat(internalformat);
         m_renderbufferBinding->setSize(width, height);
-        m_renderbufferBinding->deleteEmulatedStencilBuffer(m_context.get());
+        m_renderbufferBinding->deleteEmulatedStencilBuffer(m_context);
         break;
     case GL_DEPTH_STENCIL_OES:
         if (isDepthStencilSupported()) {
@@ -3463,14 +3463,14 @@ void WebGLRenderingContext::texImage2D(GLenum target, GLint level, GLenum intern
     if (GL_TEXTURE_2D == target && texture) {
         if (!canvas->is3D()) {
             ImageBuffer* buffer = canvas->buffer();
-            if (buffer && buffer->copyToPlatformTexture(m_context.get(), texture->object(), internalformat, type,
+            if (buffer && buffer->copyToPlatformTexture(m_context, 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());
-            if (gl && gl->m_drawingBuffer->copyToPlatformTexture(m_context.get(), texture->object(), internalformat, type,
+            if (gl && gl->m_drawingBuffer->copyToPlatformTexture(m_context, texture->object(), internalformat, type,
                 level, m_unpackPremultiplyAlpha, m_unpackFlipY)) {
                 texture->setLevelInfo(target, level, internalformat, canvas->width(), canvas->height(), type);
                 return;
@@ -3510,7 +3510,7 @@ void WebGLRenderingContext::texImage2D(GLenum target, GLint level, GLenum intern
     // 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)) {
+        if (video->copyVideoTextureToPlatformTexture(m_context, texture->object(), level, type, internalformat, m_unpackPremultiplyAlpha, m_unpackFlipY)) {
             texture->setLevelInfo(target, level, internalformat, video->videoWidth(), video->videoHeight(), type);
             return;
         }
@@ -4004,7 +4004,7 @@ void WebGLRenderingContext::useProgram(WebGLProgram* program)
     }
     if (m_currentProgram != program) {
         if (m_currentProgram)
-            m_currentProgram->onDetached(m_context.get());
+            m_currentProgram->onDetached(m_context);
         m_currentProgram = program;
         m_context->useProgram(objectOrZero(program));
         if (program)
@@ -4218,13 +4218,13 @@ void WebGLRenderingContext::forceRestoreContext()
 
 blink::WebLayer* WebGLRenderingContext::platformLayer() const
 {
-    return m_drawingBuffer->platformLayer();
+    return isContextLost() ? 0 : m_drawingBuffer->platformLayer();
 }
 
 Extensions3DUtil* WebGLRenderingContext::extensionsUtil()
 {
     if (!m_extensionsUtil)
-        m_extensionsUtil = adoptPtr(new Extensions3DUtil(m_context.get()));
+        m_extensionsUtil = adoptPtr(new Extensions3DUtil(m_context));
     return m_extensionsUtil.get();
 }
 
@@ -5199,7 +5199,7 @@ bool WebGLRenderingContext::validateDrawArrays(const char* functionName, GLenum
     }
 
     const char* reason = "framebuffer incomplete";
-    if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context.get(), &reason)) {
+    if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context, &reason)) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, functionName, reason);
         return false;
     }
@@ -5249,7 +5249,7 @@ bool WebGLRenderingContext::validateDrawElements(const char* functionName, GLenu
     }
 
     const char* reason = "framebuffer incomplete";
-    if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context.get(), &reason)) {
+    if (m_framebufferBinding && !m_framebufferBinding->onAccess(m_context, &reason)) {
         synthesizeGLError(GL_INVALID_FRAMEBUFFER_OPERATION, functionName, reason);
         return false;
     }
@@ -5388,7 +5388,16 @@ void WebGLRenderingContext::maybeRestoreContext(Timer<WebGLRenderingContext>*)
 
     blink::WebGraphicsContext3D::Attributes attributes = m_requestedAttributes->attributes(canvas()->document().topDocument()->url().string(), settings);
     OwnPtr<blink::WebGraphicsContext3D> context = adoptPtr(blink::Platform::current()->createOffscreenGraphicsContext3D(attributes));
-    if (!context) {
+
+    ASSERT(!m_drawingBuffer);
+    if (context) {
+        RefPtr<WebGLRenderingContextEvictionManager> contextEvictionManager = adoptRef(new WebGLRenderingContextEvictionManager());
+        DrawingBuffer::PreserveDrawingBuffer preserve = m_requestedAttributes->preserveDrawingBuffer() ? DrawingBuffer::Preserve : DrawingBuffer::Discard;
+        m_drawingBuffer = DrawingBuffer::create(context.release(), clampedCanvasSize(), preserve, contextEvictionManager.release());
+    }
+
+    bool failToRestore = !m_drawingBuffer;
+    if (failToRestore) {
         if (m_contextLostMode == RealLostContext) {
             m_restoreTimer.startOneShot(secondsBetweenRestoreAttempts);
         } else {
@@ -5398,21 +5407,11 @@ void WebGLRenderingContext::maybeRestoreContext(Timer<WebGLRenderingContext>*)
         return;
     }
 
-    RefPtr<WebGLRenderingContextEvictionManager> contextEvictionManager = adoptRef(new WebGLRenderingContextEvictionManager());
-
-    // Construct a new drawing buffer with the new WebGraphicsContext3D.
-    m_drawingBuffer->releaseResources();
-    DrawingBuffer::PreserveDrawingBuffer preserve = m_requestedAttributes->preserveDrawingBuffer() ? DrawingBuffer::Preserve : DrawingBuffer::Discard;
-    m_drawingBuffer = DrawingBuffer::create(context.get(), clampedCanvasSize(), preserve, contextEvictionManager.release());
-
-    if (m_drawingBuffer->isZeroSized())
-        return;
-
     m_drawingBuffer->bind();
 
     m_lostContextErrors.clear();
 
-    m_context = context.release();
+    m_context = m_drawingBuffer->context();
     m_contextLost = false;
 
     setupFlags();