Remove alpha/depth/stencil/antialias from WGC3D::Attributes.

third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp

 /*
  * Copyright (c) 2010, Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 72 matching lines @@
 private:
     gpu::gles2::GLES2Interface* m_gl;
     GLenum m_oldActiveTextureUnit;
     GLuint m_oldTextureUnitZeroId;
 };
 
 static bool shouldFailDrawingBufferCreationForTesting = false;
 
 } // namespace
 
-PassRefPtr<DrawingBuffer> DrawingBuffer::create(PassOwnPtr<WebGraphicsContext3DProvider> contextProvider, const IntSize& size, bool premultipliedAlpha, PreserveDrawingBuffer preserve, WebGraphicsContext3D::Attributes requestedAttributes)
+PassRefPtr<DrawingBuffer> DrawingBuffer::create(PassOwnPtr<WebGraphicsContext3DProvider> contextProvider, const IntSize& size, bool premultipliedAlpha, bool wantAlphaChannel, bool wantDepthBuffer, bool wantStencilBuffer, bool wantAntialiasing, PreserveDrawingBuffer preserve)
 {
     ASSERT(contextProvider);
 
     if (shouldFailDrawingBufferCreationForTesting) {
         shouldFailDrawingBufferCreationForTesting = false;
         return nullptr;
     }
 
     OwnPtr<Extensions3DUtil> extensionsUtil = Extensions3DUtil::create(contextProvider->contextGL());
     if (!extensionsUtil->isValid()) {
         // This might be the first time we notice that the GL context is lost.
         return nullptr;
     }
     ASSERT(extensionsUtil->supportsExtension("GL_OES_packed_depth_stencil"));
     extensionsUtil->ensureExtensionEnabled("GL_OES_packed_depth_stencil");
-    bool multisampleSupported = (extensionsUtil->supportsExtension("GL_CHROMIUM_framebuffer_multisample")
-        || extensionsUtil->supportsExtension("GL_EXT_multisampled_render_to_texture"))
+    bool multisampleSupported = wantAntialiasing
+        && (extensionsUtil->supportsExtension("GL_CHROMIUM_framebuffer_multisample")
+            || extensionsUtil->supportsExtension("GL_EXT_multisampled_render_to_texture"))
         && extensionsUtil->supportsExtension("GL_OES_rgb8_rgba8");
     if (multisampleSupported) {
         extensionsUtil->ensureExtensionEnabled("GL_OES_rgb8_rgba8");
         if (extensionsUtil->supportsExtension("GL_CHROMIUM_framebuffer_multisample"))
             extensionsUtil->ensureExtensionEnabled("GL_CHROMIUM_framebuffer_multisample");
         else
             extensionsUtil->ensureExtensionEnabled("GL_EXT_multisampled_render_to_texture");
     }
     bool discardFramebufferSupported = extensionsUtil->supportsExtension("GL_EXT_discard_framebuffer");
     if (discardFramebufferSupported)
         extensionsUtil->ensureExtensionEnabled("GL_EXT_discard_framebuffer");
 
-    RefPtr<DrawingBuffer> drawingBuffer = adoptRef(new DrawingBuffer(std::move(contextProvider), extensionsUtil.release(), multisampleSupported, discardFramebufferSupported, premultipliedAlpha, preserve, requestedAttributes));
-    if (!drawingBuffer->initialize(size)) {
+    RefPtr<DrawingBuffer> drawingBuffer = adoptRef(new DrawingBuffer(std::move(contextProvider), extensionsUtil.release(), discardFramebufferSupported, wantAlphaChannel, premultipliedAlpha, preserve));
+    if (!drawingBuffer->initialize(size, wantDepthBuffer, wantStencilBuffer, multisampleSupported)) {
         drawingBuffer->beginDestruction();
         return PassRefPtr<DrawingBuffer>();
     }
     return drawingBuffer.release();
 }
 
 void DrawingBuffer::forceNextDrawingBufferCreationToFail()
 {
     shouldFailDrawingBufferCreationForTesting = true;
 }
 
-DrawingBuffer::DrawingBuffer(PassOwnPtr<WebGraphicsContext3DProvider> contextProvider, PassOwnPtr<Extensions3DUtil> extensionsUtil, bool multisampleExtensionSupported, bool discardFramebufferSupported, bool premultipliedAlpha, PreserveDrawingBuffer preserve, WebGraphicsContext3D::Attributes requestedAttributes)
+DrawingBuffer::DrawingBuffer(
+    PassOwnPtr<WebGraphicsContext3DProvider> contextProvider,
+    PassOwnPtr<Extensions3DUtil> extensionsUtil,
+    bool discardFramebufferSupported,
+    bool wantAlphaChannel,
+    bool premultipliedAlpha,
+    PreserveDrawingBuffer preserve)
     : m_preserveDrawingBuffer(preserve)
     , m_scissorEnabled(false)
     , m_texture2DBinding(0)
     , m_drawFramebufferBinding(0)
     , m_readFramebufferBinding(0)
     , m_activeTextureUnit(GL_TEXTURE0)
     , m_contextProvider(std::move(contextProvider))
     , m_context(m_contextProvider->context3d())
     , m_gl(m_contextProvider->contextGL())
     , m_extensionsUtil(std::move(extensionsUtil))
     , m_size(-1, -1)
-    , m_requestedAttributes(requestedAttributes)
-    , m_multisampleExtensionSupported(multisampleExtensionSupported)
     , m_discardFramebufferSupported(discardFramebufferSupported)
+    , m_wantAlphaChannel(wantAlphaChannel)
     , m_premultipliedAlpha(premultipliedAlpha)
+    , m_hasDepthBuffer(false)
+    , m_hasStencilBuffer(false)
+    , m_hasImplicitStencilBuffer(false)
     , m_fbo(0)
     , m_depthStencilBuffer(0)
     , m_multisampleFBO(0)
     , m_multisampleColorBuffer(0)
     , m_contentsChanged(true)
     , m_contentsChangeCommitted(false)
     , m_bufferClearNeeded(false)
     , m_antiAliasingMode(None)
     , m_maxTextureSize(0)
     , m_sampleCount(0)
@@ skipping 99 matching lines @@
         (*m_newMailboxCallback)();
 
     // Resolve the multisampled buffer into m_colorBuffer texture.
     if (m_antiAliasingMode != None)
         commit();
 
     if (bitmap) {
         bitmap->setSize(size());
 
         unsigned char* pixels = bitmap->pixels();
-        bool needPremultiply = m_actualAttributes.alpha && !m_premultipliedAlpha;
+        bool needPremultiply = m_wantAlphaChannel && !m_premultipliedAlpha;
         WebGLImageConversion::AlphaOp op = needPremultiply ? WebGLImageConversion::AlphaDoPremultiply : WebGLImageConversion::AlphaDoNothing;
         if (pixels)
             readBackFramebuffer(pixels, size().width(), size().height(), ReadbackSkia, op);
     }
 
     // We must restore the texture binding since creating new textures,
     // consuming and producing mailboxes changes it.
     ScopedTextureUnit0BindingRestorer restorer(m_gl, m_activeTextureUnit, m_texture2DBinding);
 
     // First try to recycle an old buffer.
     RefPtr<MailboxInfo> frontColorBufferMailbox = recycledMailbox();
 
     // No buffer available to recycle, create a new one.
-    if (!frontColorBufferMailbox) {
+    if (!frontColorBufferMailbox)
         frontColorBufferMailbox = createNewMailbox(createTextureAndAllocateMemory(m_size));
-    }
 
     if (m_preserveDrawingBuffer == Discard) {
         std::swap(frontColorBufferMailbox->textureInfo, m_colorBuffer);
         // It appears safe to overwrite the context's framebuffer binding in the Discard case since there will always be a
         // WebGLRenderingContext::clearIfComposited() call made before the next draw call which restores the framebuffer binding.
         // If this stops being true at some point, we should track the current framebuffer binding in the DrawingBuffer and restore
         // it after attaching the new back buffer here.
         m_gl->BindFramebuffer(GL_FRAMEBUFFER, m_fbo);
         attachColorBufferToCurrentFBO();
 
@@ skipping 62 matching lines @@
     return parameters;
 #else
     return defaultTextureParameters();
 #endif
 }
 
 DrawingBuffer::TextureParameters DrawingBuffer::defaultTextureParameters()
 {
     TextureParameters parameters;
     parameters.target = GL_TEXTURE_2D;
-    if (m_requestedAttributes.alpha) {
+    if (m_wantAlphaChannel) {
         parameters.internalColorFormat = GL_RGBA;
         parameters.colorFormat = GL_RGBA;
         parameters.internalRenderbufferFormat = GL_RGBA8_OES;
     } else {
         parameters.internalColorFormat = GL_RGB;
         parameters.colorFormat = GL_RGB;
         parameters.internalRenderbufferFormat = GL_RGB8_OES;
     }
     return parameters;
 }
@@ skipping 61 matching lines @@
             deleteChromiumImageForTexture(&m_textureMailboxes[i]->textureInfo);
 
             m_gl->DeleteTextures(1, &m_textureMailboxes[i]->textureInfo.textureId);
             m_textureMailboxes.remove(i);
             return;
         }
     }
     ASSERT_NOT_REACHED();
 }
 
-bool DrawingBuffer::initialize(const IntSize& size)
+bool DrawingBuffer::initialize(const IntSize& size, bool wantDepthBuffer, bool wantStencilBuffer, bool multisampleExtensionSupported)
 {
     if (m_gl->GetGraphicsResetStatusKHR() != GL_NO_ERROR) {
         // Need to try to restore the context again later.
         return false;
     }
 
     m_gl->GetIntegerv(GL_MAX_TEXTURE_SIZE, &m_maxTextureSize);
 
     int maxSampleCount = 0;
     m_antiAliasingMode = None;
-    if (m_requestedAttributes.antialias && m_multisampleExtensionSupported) {
+    if (multisampleExtensionSupported) {
         m_gl->GetIntegerv(GL_MAX_SAMPLES_ANGLE, &maxSampleCount);
         m_antiAliasingMode = MSAAExplicitResolve;
         if (m_extensionsUtil->supportsExtension("GL_EXT_multisampled_render_to_texture")) {
             m_antiAliasingMode = MSAAImplicitResolve;
         } else if (m_extensionsUtil->supportsExtension("GL_CHROMIUM_screen_space_antialiasing")) {
             m_antiAliasingMode = ScreenSpaceAntialiasing;
         }
     }
     m_sampleCount = std::min(4, maxSampleCount);
 
     m_gl->GenFramebuffers(1, &m_fbo);
 
     m_gl->BindFramebuffer(GL_FRAMEBUFFER, m_fbo);
     createSecondaryBuffers();
-    // We first try to initialize everything with the requested attributes.
-    if (!reset(size))
+    if (!reset(size, wantDepthBuffer || wantStencilBuffer))
         return false;
-    // If that succeeds, we then see what we actually got and update our actual attributes to reflect that.
-    m_actualAttributes = m_requestedAttributes;
-    if (m_requestedAttributes.alpha) {
-        GLint alphaBits = 0;
-        m_gl->GetIntegerv(GL_ALPHA_BITS, &alphaBits);
-        m_actualAttributes.alpha = alphaBits > 0;
+
+    if (m_depthStencilBuffer) {

[danakj, 2016/03/31 22:13:02]

Explanation of preserving old behaviour:

If requested was false, we didn't branch before at all, so actual would be false
for any one of these properties. That includes depth even tho stencil was true
and we actually have depth bits, and vice versa.

So here, we continue to set hasDepth and hasStencil to false if the request was
false.

hasImplicitStencilBuffer was implemented as m_depthStencilBuffer &&
m_requestedAttributes.depth && !m_requestedAttributes.stencil

Now we check m_depthStencilBuffer still. If we have a buffer than wantDepth or
wantStencil was true (and we DCHECK that). If wantStencil is false, then that
implies that wantDepth was true, so we don't both to actually check that in the
code.

+        DCHECK(wantDepthBuffer || wantStencilBuffer);
+        m_hasDepthBuffer = wantDepthBuffer;

[piman, 2016/04/01 00:24:15]

I'm not sure hasDepthBuffer/hasStencilBuffer are that useful if they're lies.
The only non-test user (WebGLRenderingContextBase) already &&'s the result with
the requested values, so I think we could just tell the truth?

[danakj, 2016/04/01 00:40:50]

That's an excellent point. I had to think this through to confirm:

Depth lies if
- depth buffer exists
- requested depth buffer was false

In that case WebGLRCBase will not query hasDepthBuffer() at all:
    if (m_requestedAttributes.depth() && !drawingBuffer()->hasDepthBuffer())

So the fact that it lies doesn't matter.

If the request is true, it will query. But if the request is true, we never lie.
We report true if it exists and false otherwise.

So ya I agree.

There is, however, one other user of these lies, which is line 774ish in this
file. Except there they read different lies, as I've commented there.

They will be false always when called from initialize() so we won't clear.

But when reset() is called externally, we won't clear the thing we didn't
request. If we don't maintain these lies internally, we will clear the depth
buffer when one wasn't requested, or stencil.

WDYT?

[danakj, 2016/04/01 00:41:46]

Oh, and if we use !!m_depthStencilBuffer there, then we'd clear on initialize()
too.

+        m_hasStencilBuffer = wantStencilBuffer;
+        m_hasImplicitStencilBuffer = !wantStencilBuffer;
     }
-    if (m_requestedAttributes.depth) {
-        GLint depthBits = 0;
-        m_gl->GetIntegerv(GL_DEPTH_BITS, &depthBits);
-        m_actualAttributes.depth = depthBits > 0;
-    }
-    if (m_requestedAttributes.stencil) {
-        GLint stencilBits = 0;
-        m_gl->GetIntegerv(GL_STENCIL_BITS, &stencilBits);
-        m_actualAttributes.stencil = stencilBits > 0;
-    }
-    m_actualAttributes.antialias = multisample();
 
     if (m_gl->GetGraphicsResetStatusKHR() != GL_NO_ERROR) {
         // It's possible that the drawing buffer allocation provokes a context loss, so check again just in case. http://crbug.com/512302
         return false;
     }
 
     return true;
 }
 
 bool DrawingBuffer::copyToPlatformTexture(WebGraphicsContext3D* context, gpu::gles2::GLES2Interface* gl, GLuint texture, GLenum internalFormat,
@@ skipping 29 matching lines @@
         m_gl->GenSyncTokenCHROMIUM(fenceSync, mailbox.syncToken);
         mailbox.validSyncToken = true;
     }
 
     if (mailbox.validSyncToken)
         gl->WaitSyncTokenCHROMIUM(mailbox.syncToken);
     GLuint sourceTexture = gl->CreateAndConsumeTextureCHROMIUM(target, mailbox.name);
 
     GLboolean unpackPremultiplyAlphaNeeded = GL_FALSE;
     GLboolean unpackUnpremultiplyAlphaNeeded = GL_FALSE;
-    if (m_actualAttributes.alpha && m_premultipliedAlpha && !premultiplyAlpha)
+    if (m_wantAlphaChannel && m_premultipliedAlpha && !premultiplyAlpha)
         unpackUnpremultiplyAlphaNeeded = GL_TRUE;
-    else if (m_actualAttributes.alpha && !m_premultipliedAlpha && premultiplyAlpha)
+    else if (m_wantAlphaChannel && !m_premultipliedAlpha && premultiplyAlpha)
         unpackPremultiplyAlphaNeeded = GL_TRUE;
 
     gl->CopyTextureCHROMIUM(sourceTexture, texture, internalFormat, destType, flipY, unpackPremultiplyAlphaNeeded, unpackUnpremultiplyAlphaNeeded);
 
     gl->DeleteTextures(1, &sourceTexture);
 
     const GLuint64 fenceSync = gl->InsertFenceSyncCHROMIUM();
 
     gl->Flush();
     GLbyte syncToken[24];
     gl->GenSyncTokenCHROMIUM(fenceSync, syncToken);
     m_gl->WaitSyncTokenCHROMIUM(syncToken);
 
     return true;
 }
 
 GLuint DrawingBuffer::framebuffer() const
 {
     return m_fbo;
 }
 
 WebLayer* DrawingBuffer::platformLayer()
 {
     if (!m_layer) {
         m_layer = adoptPtr(Platform::current()->compositorSupport()->createExternalTextureLayer(this));
 
-        m_layer->setOpaque(!m_actualAttributes.alpha);
-        m_layer->setBlendBackgroundColor(m_actualAttributes.alpha);
+        m_layer->setOpaque(!m_wantAlphaChannel);
+        m_layer->setBlendBackgroundColor(m_wantAlphaChannel);
         m_layer->setPremultipliedAlpha(m_premultipliedAlpha);
         m_layer->setNearestNeighbor(m_filterQuality == kNone_SkFilterQuality);
         GraphicsLayer::registerContentsLayer(m_layer->layer());
     }
 
     return m_layer->layer();
 }
 
 void DrawingBuffer::clearPlatformLayer()
 {
@@ skipping 58 matching lines @@
 void DrawingBuffer::createSecondaryBuffers()
 {
     // create a multisample FBO
     if (m_antiAliasingMode == MSAAExplicitResolve) {
         m_gl->GenFramebuffers(1, &m_multisampleFBO);
         m_gl->BindFramebuffer(GL_FRAMEBUFFER, m_multisampleFBO);
         m_gl->GenRenderbuffers(1, &m_multisampleColorBuffer);
     }
 }
 
-bool DrawingBuffer::resizeFramebuffer(const IntSize& size)
+bool DrawingBuffer::resizeFramebuffer(const IntSize& size, bool wantDepthOrStencilBuffer)
 {
     m_gl->BindFramebuffer(GL_FRAMEBUFFER, m_fbo);
-    if (m_antiAliasingMode != MSAAExplicitResolve)
+    if (m_antiAliasingMode != MSAAExplicitResolve && wantDepthOrStencilBuffer)
         resizeDepthStencil(size);
     if (m_gl->CheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
         return false;
 
     return true;
 }
 
-bool DrawingBuffer::resizeMultisampleFramebuffer(const IntSize& size)
+bool DrawingBuffer::resizeMultisampleFramebuffer(const IntSize& size, bool wantDepthOrStencilBuffer)
 {
     if (m_antiAliasingMode == MSAAExplicitResolve) {
         m_gl->BindFramebuffer(GL_FRAMEBUFFER, m_multisampleFBO);
 
         m_gl->BindRenderbuffer(GL_RENDERBUFFER, m_multisampleColorBuffer);
         m_gl->RenderbufferStorageMultisampleCHROMIUM(GL_RENDERBUFFER, m_sampleCount, m_colorBuffer.parameters.internalRenderbufferFormat, size.width(), size.height());
 
         if (m_gl->GetError() == GL_OUT_OF_MEMORY)
             return false;
 
         m_gl->FramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, m_multisampleColorBuffer);
-        resizeDepthStencil(size);
+        if (wantDepthOrStencilBuffer)
+            resizeDepthStencil(size);
         if (m_gl->CheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
             return false;
     }
 
     return true;
 }
 
 void DrawingBuffer::resizeDepthStencil(const IntSize& size)
 {
-    if (!m_requestedAttributes.depth && !m_requestedAttributes.stencil)
-        return;
-
     if (!m_depthStencilBuffer)
         m_gl->GenRenderbuffers(1, &m_depthStencilBuffer);
     m_gl->BindRenderbuffer(GL_RENDERBUFFER, m_depthStencilBuffer);
     if (m_antiAliasingMode == MSAAImplicitResolve)
         m_gl->RenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, m_sampleCount, GL_DEPTH24_STENCIL8_OES, size.width(), size.height());
     else if (m_antiAliasingMode == MSAAExplicitResolve)
         m_gl->RenderbufferStorageMultisampleCHROMIUM(GL_RENDERBUFFER, m_sampleCount, GL_DEPTH24_STENCIL8_OES, size.width(), size.height());
     else
         m_gl->RenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8_OES, size.width(), size.height());
     m_gl->FramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, m_depthStencilBuffer);
     m_gl->BindRenderbuffer(GL_RENDERBUFFER, 0);
 }
 
 
 
 void DrawingBuffer::clearFramebuffers(GLbitfield clearMask)
 {
     // We will clear the multisample FBO, but we also need to clear the non-multisampled buffer.
     if (m_multisampleFBO) {
         m_gl->BindFramebuffer(GL_FRAMEBUFFER, m_fbo);
         m_gl->Clear(GL_COLOR_BUFFER_BIT);
     }
 
     m_gl->BindFramebuffer(GL_FRAMEBUFFER, m_multisampleFBO ? m_multisampleFBO : m_fbo);
     m_gl->Clear(clearMask);
 }
 
-bool DrawingBuffer::hasImplicitStencilBuffer() const
-{
-    return m_depthStencilBuffer && m_requestedAttributes.depth && !m_requestedAttributes.stencil;
-}
-
 void DrawingBuffer::setSize(const IntSize& size)
 {
     if (m_size == size)
         return;
 
     m_size = size;
 }
 
 IntSize DrawingBuffer::adjustSize(const IntSize& desiredSize, const IntSize& curSize, int maxTextureSize)
 {
     IntSize adjustedSize = desiredSize;
 
     // Clamp if the desired size is greater than the maximum texture size for the device.
     if (adjustedSize.height() > maxTextureSize)
         adjustedSize.setHeight(maxTextureSize);
 
     if (adjustedSize.width() > maxTextureSize)
         adjustedSize.setWidth(maxTextureSize);
 
     return adjustedSize;
 }
 
-bool DrawingBuffer::reset(const IntSize& newSize)
+bool DrawingBuffer::reset(const IntSize& newSize, bool wantDepthOrStencilBuffer)
 {
     ASSERT(!newSize.isEmpty());
     IntSize adjustedSize = adjustSize(newSize, m_size, m_maxTextureSize);
     if (adjustedSize.isEmpty())
         return false;
 
     if (adjustedSize != m_size) {
         do {
             if (m_colorBuffer.textureId) {
                 resizeTextureMemory(&m_colorBuffer, adjustedSize);
             } else {
                 m_colorBuffer = createTextureAndAllocateMemory(adjustedSize);
             }
 
             m_gl->BindFramebuffer(GL_FRAMEBUFFER, m_fbo);
             attachColorBufferToCurrentFBO();
 
             // resize multisample FBO
-            if (!resizeMultisampleFramebuffer(adjustedSize) || !resizeFramebuffer(adjustedSize)) {
+            if (!resizeMultisampleFramebuffer(adjustedSize, wantDepthOrStencilBuffer)
+                || !resizeFramebuffer(adjustedSize, wantDepthOrStencilBuffer)) {
                 adjustedSize.scale(s_resourceAdjustedRatio);
                 continue;
             }
             break;
         } while (!adjustedSize.isEmpty());
 
         setSize(adjustedSize);
 
         if (adjustedSize.isEmpty())
             return false;
     }
 
     m_gl->Disable(GL_SCISSOR_TEST);
     m_gl->ClearColor(0, 0, 0, 0);
     m_gl->ColorMask(true, true, true, true);
 
     GLbitfield clearMask = GL_COLOR_BUFFER_BIT;
-    if (m_actualAttributes.depth) {
+    if (m_hasDepthBuffer) {

[danakj, 2016/03/31 22:13:02]

I will point out while I'm here that it's a bit weird we're branching on *has*
depth/stencil here (or on the actual attributes before), since those are not set
when this is called from initialize() until after this method returns.

         m_gl->ClearDepthf(1.0f);
         clearMask |= GL_DEPTH_BUFFER_BIT;
         m_gl->DepthMask(true);
     }
-    if (m_actualAttributes.stencil) {
+    if (m_hasStencilBuffer) {
         m_gl->ClearStencil(0);
         clearMask |= GL_STENCIL_BUFFER_BIT;
         m_gl->StencilMaskSeparate(GL_FRONT, 0xFFFFFFFF);
     }
 
     clearFramebuffers(clearMask);
     return true;
 }
 
 void DrawingBuffer::commit()
@@ skipping 160 matching lines @@
         m_gl->DestroyImageCHROMIUM(info->imageId);
         info->imageId = 0;
     }
 }
 
 DrawingBuffer::TextureInfo DrawingBuffer::createTextureAndAllocateMemory(const IntSize& size)
 {
     // TODO(erikchen): Add support for a CHROMIUM_image back buffer whose
     // behavior mimics a texture with internal format GL_RGB.
     // https://crbug.com/581777.
-    if (!m_requestedAttributes.alpha)
+    if (!m_wantAlphaChannel)
         return createDefaultTextureAndAllocateMemory(size);
 
     if (!RuntimeEnabledFeatures::webGLImageChromiumEnabled())
         return createDefaultTextureAndAllocateMemory(size);
 
     // First, try to allocate a CHROMIUM_image. This always has the potential to
     // fail.
     TextureParameters parameters = chromiumImageTextureParameters();
     GLuint imageId = m_gl->CreateGpuMemoryBufferImageCHROMIUM(size.width(), size.height(), parameters.internalColorFormat, GC3D_SCANOUT_CHROMIUM);
     if (!imageId)
@@ skipping 51 matching lines @@
 
     if (m_antiAliasingMode == MSAAImplicitResolve)
         m_gl->FramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, target, m_colorBuffer.textureId, 0, m_sampleCount);
     else
         m_gl->FramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, target, m_colorBuffer.textureId, 0);
 
     m_gl->BindTexture(GL_TEXTURE_2D, m_texture2DBinding);
 }
 
 } // namespace blink