optimizing layout performance when only transform3d matrix changed by

Source/core/frame/FrameView.cpp

Index: Source/core/frame/FrameView.cpp
===================================================================
--- Source/core/frame/FrameView.cpp	(revision 169401)
+++ Source/core/frame/FrameView.cpp	(working copy)
@@ -606,7 +606,7 @@
     }
 }
 
-void FrameView::updateCompositingLayersAfterStyleChange()
+void FrameView::updateCompositingLayersAfterStyleChange(bool fast)
 {
     TRACE_EVENT0("webkit", "FrameView::updateCompositingLayersAfterStyleChange");
     RenderView* renderView = this->renderView();
@@ -629,8 +629,8 @@
     // need to do this if a layout is not already scheduled.
     if (!needsLayout())
         renderView->compositor()->updateCompositingRequirementsState();
-
-    renderView->compositor()->setNeedsCompositingUpdate(CompositingUpdateAfterStyleChange);
+    CompositingUpdateType update = fast? CompositingMinUpdateAfterStyleChange: CompositingUpdateAfterStyleChange;
+    renderView->compositor()->setNeedsCompositingUpdate(update);
 }
 
 void FrameView::updateCompositingLayersAfterLayout()