Reduce compositing update in Silk's toggle_drawer by 20%

Source/core/rendering/compositing/RenderLayerCompositor.h

 /*
  * 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 11 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef RenderLayerCompositor_h
 #define RenderLayerCompositor_h
 
 #include "core/page/ChromeClient.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/compositing/CompositingReasonFinder.h"
+#include "core/rendering/compositing/GraphicsLayerUpdater.h"
 #include "platform/graphics/GraphicsLayerClient.h"
 #include "wtf/HashMap.h"
 
 namespace WebCore {
 
 class FixedPositionViewportConstraints;
 class GraphicsLayer;
 class RenderEmbeddedObject;
 class RenderLayerStackingNode;
 class RenderPart;
@@ skipping 291 matching lines @@
     OwnPtr<GraphicsLayer> m_rootTransformLayer;
 
     CompositingReasonFinder m_compositingReasonFinder;
 
     bool m_hasAcceleratedCompositing;
     bool m_showRepaintCounter;
 
     // FIXME: This should absolutely not be mutable.
     mutable bool m_needsToRecomputeCompositingRequirements;
     bool m_needsToUpdateLayerTreeGeometry;
+    GraphicsLayerUpdater::UpdateType m_pendingUpdateType;
 
     bool m_compositing;
     bool m_compositingLayersNeedRebuild;
     bool m_forceCompositingMode;
     bool m_needsUpdateCompositingRequirementsState;
 
     bool m_isTrackingRepaints; // Used for testing.
 
     RootLayerAttachment m_rootLayerAttachment;
 
@@ skipping 17 matching lines @@
     OwnPtr<GraphicsLayer> m_layerForScrollCorner;
 #if USE(RUBBER_BANDING)
     OwnPtr<GraphicsLayer> m_layerForOverhangShadow;
 #endif
 };
 
 
 } // namespace WebCore
 
 #endif // RenderLayerCompositor_h