Delete a bunch of noop paint invalidation code.

sky/engine/core/html/HTMLCanvasElement.cpp

 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. 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.
@@ skipping 198 matching lines @@
 {
     if (m_dirtyRect.isEmpty())
         return;
     m_finalizeFrameTask.Cancel();
     m_dirtyRect = FloatRect();
 }
 
 void HTMLCanvasElement::finalizeFrameMicrotask()
 {
     // This method gets invoked if didDraw was called earlier in the current task.
-    ASSERT(!m_dirtyRect.isEmpty());
     if (is3D()) {
         didFinalizeFrame();
     } else {
         ASSERT(hasImageBuffer());
-        m_imageBuffer->finalizeFrame(m_dirtyRect);
+        m_imageBuffer->finalizeFrame();
     }
-    ASSERT(m_dirtyRect.isEmpty());
     ASSERT(m_finalizeFrameTask.IsCancelled());
 }
 
 void HTMLCanvasElement::notifyObserversCanvasChanged(const FloatRect& rect)
 {
     HashSet<RawPtr<CanvasObserver> >::iterator end = m_observers.end();
     for (HashSet<RawPtr<CanvasObserver> >::iterator it = m_observers.begin(); it != end; ++it)
         (*it)->canvasChanged(this, rect);
 }
 
@@ skipping 423 matching lines @@
     }
     return m_imageBuffer->copyImage(DontCopyBackingStore, Unscaled);
 }
 
 FloatSize HTMLCanvasElement::sourceSize() const
 {
     return FloatSize(width(), height());
 }
 
 }