Make the compositing assert disabler for paint invalidation more targeted.

Source/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 25 matching lines @@
 #include "core/dom/ExceptionCode.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/html/ImageData.h"
 #include "core/html/canvas/Canvas2DContextAttributes.h"
 #include "core/html/canvas/CanvasRenderingContext2D.h"
 #include "core/html/canvas/WebGLContextAttributes.h"
 #include "core/html/canvas/WebGLContextEvent.h"
 #include "core/html/canvas/WebGLRenderingContext.h"
 #include "core/rendering/RenderHTMLCanvas.h"
+#include "core/rendering/RenderLayer.h"
 #include "platform/MIMETypeRegistry.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/graphics/Canvas2DImageBufferSurface.h"
 #include "platform/graphics/GraphicsContextStateSaver.h"
 #include "platform/graphics/ImageBuffer.h"
 #include "platform/graphics/RecordingImageBufferSurface.h"
 #include "platform/graphics/UnacceleratedImageBufferSurface.h"
 #include "platform/graphics/gpu/WebGLImageBufferSurface.h"
 #include "platform/transforms/AffineTransform.h"
 #include "public/platform/Platform.h"
@@ skipping 149 matching lines @@
 {
     if (m_dirtyRect.isEmpty())
         return;
 
     // Propagate the m_dirtyRect accumulated so far to the compositor
     // before restarting with a blank dirty rect.
     FloatRect srcRect(0, 0, size().width(), size().height());
     m_dirtyRect.intersect(srcRect);
     if (RenderBox* ro = renderBox()) {
         FloatRect mappedDirtyRect = mapRect(m_dirtyRect, srcRect, ro->contentBoxRect());
+        // For querying RenderLayer::compositingState()
+        // FIXME: is this invalidation using the correct compositing state?
+        DisableCompositingQueryAsserts disabler;
         ro->invalidatePaintRectangle(enclosingIntRect(mappedDirtyRect));
     }
     notifyObserversCanvasChanged(m_dirtyRect);
     blink::Platform::current()->currentThread()->removeTaskObserver(this);
     m_dirtyRect = FloatRect();
 }
 
 void HTMLCanvasElement::resetDirtyRect()
 {
     if (m_dirtyRect.isEmpty())
@@ skipping 512 matching lines @@
 {
     return !originClean();
 }
 
 FloatSize HTMLCanvasElement::sourceSize() const
 {
     return FloatSize(width(), height());
 }
 
 }