Set root clip layer not to maskToBounds.

Source/web/PinchViewports.h

Index: Source/web/PinchViewports.h
diff --git a/Source/web/PinchViewports.h b/Source/web/PinchViewports.h
index f1dbf6ecdc10d54aee93df43a493e82caa9d9ac4..35a41c43a78b36f08d99fa6d042fa897383d6311 100644
--- a/Source/web/PinchViewports.h
+++ b/Source/web/PinchViewports.h
@@ -59,7 +59,7 @@ public:
     void setOverflowControlsHostLayer(WebCore::GraphicsLayer*);
     WebCore::GraphicsLayer* rootGraphicsLayer()
     {
-        return m_innerViewportClipLayer.get();
+        return m_innerViewportContainerLayer.get();
     }
     void setViewportSize(const WebCore::IntSize&);
 
@@ -76,7 +76,7 @@ private:
     void setupScrollbar(WebKit::WebScrollbar::Orientation);
 
     WebViewImpl* m_owner;
-    OwnPtr<WebCore::GraphicsLayer> m_innerViewportClipLayer;
+    OwnPtr<WebCore::GraphicsLayer> m_innerViewportContainerLayer;
     OwnPtr<WebCore::GraphicsLayer> m_pageScaleLayer;
     OwnPtr<WebCore::GraphicsLayer> m_innerViewportScrollLayer;
     OwnPtr<WebCore::GraphicsLayer> m_overlayScrollbarHorizontal;