Share Group plumbing in Blink; Remove WebGL from default share group

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
@@ skipping 815 matching lines @@
     clearIfComposited();
 
     if (!m_markedCanvasDirty && !m_layerCleared)
         return;
 
     canvas()->clearCopiedImage();
     m_markedCanvasDirty = false;
 
     m_drawingBuffer->commit();
     if (!(canvas()->buffer())->copyRenderingResultsFromDrawingBuffer(m_drawingBuffer.get())) {
+        restoreCurrentTexture2D();
         canvas()->ensureUnacceleratedImageBuffer();
         if (canvas()->hasImageBuffer())
             m_drawingBuffer->paintRenderingResultsToCanvas(canvas()->buffer());
+    } else {
+        restoreCurrentTexture2D();
     }
 
     if (m_framebufferBinding)
         m_context->bindFramebuffer(GL_FRAMEBUFFER, objectOrZero(m_framebufferBinding.get()));
     else
         m_drawingBuffer->bind();
 }
 
 PassRefPtr<ImageData> WebGLRenderingContextBase::paintRenderingResultsToImageData()
 {
@@ skipping 2558 matching lines @@
 
     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);
+                restoreCurrentTexture2D();
                 return;
             }
         } else {
             WebGLRenderingContextBase* gl = toWebGLRenderingContextBase(canvas->renderingContext());
             if (gl && gl->m_drawingBuffer->copyToPlatformTexture(m_context.get(), texture->object(), internalformat, type,

[Ken Russell (switch to Gerrit), 2014/03/13 19:35:54]

If the save/restore in DrawingBuffer::copyToPlatformTexture were removed, then
it would also be necessary to restore the TEXTURE_2D binding on the context
"gl", not just "this". Actually, I think it'll always be destroying the
TEXTURE_2D binding against "gl" as it's currently written. Please double-check,
and try to write a regression test if there's a bug here.

                 level, m_unpackPremultiplyAlpha, m_unpackFlipY)) {
                 texture->setLevelInfo(target, level, internalformat, canvas->width(), canvas->height(), type);
+                restoreCurrentTexture2D();
                 return;
             }
         }
+        restoreCurrentTexture2D();

[Ken Russell (switch to Gerrit), 2014/03/13 19:35:54]

It might be worth creating a class which makes the restoreCurrentTexture2D()
call in its destructor, and stack-allocating an instance higher up in this block
so that all code paths implicitly execute it before exit.

     }
 
     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> WebGLRenderingContextBase::videoFrameToImage(HTMLVideoElement* video, BackingStoreCopy backingStoreCopy)
@@ skipping 1894 matching lines @@
     LocalFrame* frame = canvas()->document().frame();
     if (!frame)
         return;
 
     Settings* settings = frame->settings();
 
     if (!frame->loader().client()->allowWebGL(settings && settings->webGLEnabled()))
         return;
 
     blink::WebGraphicsContext3D::Attributes attributes = m_requestedAttributes->attributes(canvas()->document().topDocument().url().string(), settings);
-    OwnPtr<blink::WebGraphicsContext3D> context = adoptPtr(blink::Platform::current()->createOffscreenGraphicsContext3D(attributes));
+    OwnPtr<blink::WebGraphicsContext3D> context = adoptPtr(blink::Platform::current()->createOffscreenGraphicsContext3D(attributes, 0));
     if (!context) {
         if (m_contextLostMode == RealLostContext) {
             m_restoreTimer.startOneShot(secondsBetweenRestoreAttempts, FROM_HERE);
         } else {
             // This likely shouldn't happen but is the best way to report it to the WebGL app.
             synthesizeGLError(GL_INVALID_OPERATION, "", "error restoring context");
         }
         return;
     }
 
@@ skipping 207 matching lines @@
         if (m_textureUnits[i].m_texture2DBinding
             || m_textureUnits[i].m_textureCubeMapBinding) {
             m_onePlusMaxNonDefaultTextureUnit = i + 1;
             return;
         }
     }
     m_onePlusMaxNonDefaultTextureUnit = 0;
 }
 
 } // namespace WebCore