Refactoring ImageBuffer to decouple it from Canvas2DLayerBridge

Source/core/html/canvas/WebGLRenderingContext.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 57 matching lines @@
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderClient.h"
 #include "core/frame/Frame.h"
 #include "core/page/Settings.h"
 #include "core/platform/graphics/Extensions3D.h"
 #include "core/platform/graphics/gpu/DrawingBuffer.h"
 #include "core/rendering/RenderBox.h"
 #include "platform/NotImplemented.h"
 #include "platform/geometry/IntSize.h"
+#include "platform/graphics/UnacceleratedImageBufferSurface.h"
 
 #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;
@@ skipping 5363 matching lines @@
     for (i = 0; i < m_capacity; ++i) {
         ImageBuffer* buf = m_buffers[i].get();
         if (!buf)
             break;
         if (buf->logicalSize() != size)
             continue;
         bubbleToFront(i);
         return buf;
     }
 
-    OwnPtr<ImageBuffer> temp = ImageBuffer::create(size, 1);
-    if (!temp)
+    OwnPtr<ImageBufferSurface> surface = adoptPtr(new UnacceleratedImageBufferSurface(size));
+    if (!surface->isValid())

[Stephen White, 2013/12/04 21:18:40]

Do we need a null ptr check here?

         return 0;
+    OwnPtr<ImageBuffer> temp = adoptPtr(new ImageBuffer(surface.release()));
     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)
 {
@@ skipping 145 matching lines @@
         if (m_textureUnits[i].m_texture2DBinding
             || m_textureUnits[i].m_textureCubeMapBinding) {
             m_onePlusMaxNonDefaultTextureUnit = i + 1;
             return;
         }
     }
     m_onePlusMaxNonDefaultTextureUnit = 0;
 }
 
 } // namespace WebCore