Turn off computation of the interest rect in cc in synchronized paint mode.

third_party/WebKit/public/platform/WebContentLayerClient.h

 /*
  * Copyright (C) 2011 Google 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
@@ skipping 10 matching lines @@
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (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 WebContentLayerClient_h
 #define WebContentLayerClient_h
 
 #include "WebCommon.h"
 
+namespace gfx {
+class Rect;
+}
+
 namespace blink {
 
+struct WebRect;
 class WebDisplayItemList;
-struct WebRect;
 
 class BLINK_PLATFORM_EXPORT WebContentLayerClient {
 public:
     enum PaintingControlSetting {
         PaintDefaultBehavior,
         DisplayListConstructionDisabled,
         DisplayListCachingDisabled,
         DisplayListPaintingDisabled
     };
 
+    virtual gfx::Rect paintableRegion() = 0;
+
     // Paints the content area for the layer, typically dirty rects submitted
     // through WebContentLayer::setNeedsDisplayInRect, submitting drawing commands
     // to populate the WebDisplayItemList.
     // The |clip| rect defines the region of interest. The resulting WebDisplayItemList should contain
     // sufficient content to correctly paint the rect, but may also contain other content. The result
     // will be clipped on playback.
     // The |PaintingControlSetting| enum controls painting to isolate different components in performance tests.
     // Currently the DisplayListConstructionDisabled does nothing.
     virtual void paintContents(
         WebDisplayItemList*,
         const WebRect& clip,
         PaintingControlSetting = PaintDefaultBehavior) = 0;
 
     // Returns an estimate of the current memory usage within this object,
     // excluding memory shared with painting artifacts (i.e.,
     // WebDisplayItemList). Should be invoked after paintContents, so that the
     // result includes data cached internally during painting.
     virtual size_t approximateUnsharedMemoryUsage() const { return 0; }
 
 protected:
     virtual ~WebContentLayerClient() { }
 };
 
 } // namespace blink
 
 #endif // WebContentLayerClient_h