Remove dead code related to compositing from Sky

sky/engine/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 762 matching lines @@
 }
 
 void WebGLRenderingContextBase::markContextChanged(ContentChangeType changeType)
 {
     if (m_framebufferBinding || isContextLost())
         return;
 
     drawingBuffer()->markContentsChanged();
 
     m_layerCleared = false;
-    RenderBox* renderBox = canvas()->renderBox();
-    if (renderBox && renderBox->hasAcceleratedCompositing()) {
+    if (!m_markedCanvasDirty) {
         m_markedCanvasDirty = true;
-        canvas()->clearCopiedImage();
-    } else {
-        if (!m_markedCanvasDirty) {
-            m_markedCanvasDirty = true;
-            canvas()->didDraw(FloatRect(FloatPoint(0, 0), clampedCanvasSize()));
-        }
+        canvas()->didDraw(FloatRect(FloatPoint(0, 0), clampedCanvasSize()));
     }
 }
 
 bool WebGLRenderingContextBase::clearIfComposited(GLbitfield mask)
 {
     if (isContextLost())
         return false;
 
     if (!drawingBuffer()->layerComposited() || m_layerCleared
         || m_requestedAttributes->preserveDrawingBuffer() || (mask && m_framebufferBinding))
@@ skipping 4808 matching lines @@
     return m_sharedWebGraphicsContext3D ? m_sharedWebGraphicsContext3D->drawingBuffer() : 0;
 }
 #else
 DrawingBuffer* WebGLRenderingContextBase::drawingBuffer() const
 {
     return m_drawingBuffer.get();
 }
 #endif
 
 } // namespace blink