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

third_party/WebKit/public/platform/WebContentLayerClient.h

Index: third_party/WebKit/public/platform/WebContentLayerClient.h
diff --git a/third_party/WebKit/public/platform/WebContentLayerClient.h b/third_party/WebKit/public/platform/WebContentLayerClient.h
index 7e28aeeec6436c7b7b08faaa1ca92d776f8c6b3f..9447a8b80017c9e0818e8f5d78516ba9e33a9e4d 100644
--- a/third_party/WebKit/public/platform/WebContentLayerClient.h
+++ b/third_party/WebKit/public/platform/WebContentLayerClient.h
@@ -28,10 +28,13 @@
 
 #include "WebCommon.h"
 
+namespace gfx {
+class Rect;
+}
+
 namespace blink {
 
 class WebDisplayItemList;
-struct WebRect;
 
 class BLINK_PLATFORM_EXPORT WebContentLayerClient {
 public:
@@ -45,14 +48,15 @@ public:
     // 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 |recordingViewport| rect defines the region of interest. |recordingViewport| may be set by the callee to a
+    // different value. The resulting WebDisplayItemList should contain
+    // sufficient content to correctly paint the final value of |recordingViewport|, but may also contain other content.
+    // The result will be clipped on playback to the final value of |recordingViewport|.
     // The |PaintingControlSetting| enum controls painting to isolate different components in performance tests.
-    // Currently the DisplayListConstructionDisabled does nothing.
+    // Currently DisplayListConstructionDisabled does nothing.
     virtual void paintContents(
         WebDisplayItemList*,
-        const WebRect& clip,
+        gfx::Rect* recordingViewport,
         PaintingControlSetting = PaintDefaultBehavior) = 0;
 
     // Returns an estimate of the current memory usage within this object,