Reland of place pinch scrollbars with regular scrollbars.

Source/core/layout/compositing/CompositedDeprecatedPaintLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 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 12 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 
 #include "core/layout/compositing/CompositedDeprecatedPaintLayerMapping.h"
 
 #include "core/HTMLNames.h"
 #include "core/dom/DOMNodeIds.h"
 #include "core/fetch/ImageResource.h"
+#include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/RemoteFrame.h"
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLIFrameElement.h"
 #include "core/html/HTMLMediaElement.h"
 #include "core/html/HTMLVideoElement.h"
 #include "core/html/canvas/CanvasRenderingContext.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/layout/LayoutEmbeddedObject.h"
 #include "core/layout/LayoutHTMLCanvas.h"
@@ skipping 1011 matching lines @@
             bottomLayer = layer;
         }
     };
 
     updateBottomLayer(m_childTransformLayer.get());
     updateBottomLayer(m_childContainmentLayer.get());
     updateBottomLayer(m_scrollingLayer.get());
 
     // Now constructing the subtree for the overflow controls.
     bottomLayer = m_graphicsLayer.get();
+    if (m_isMainFrameLayoutViewLayer)
+        bottomLayer = layoutObject()->frame()->page()->frameHost().visualViewport().containerLayer();
     updateBottomLayer(m_overflowControlsClippingLayer.get());
     updateBottomLayer(m_overflowControlsHostLayer.get());
     if (m_layerForHorizontalScrollbar)
         m_overflowControlsHostLayer->addChild(m_layerForHorizontalScrollbar.get());
     if (m_layerForVerticalScrollbar)
         m_overflowControlsHostLayer->addChild(m_layerForVerticalScrollbar.get());
     if (m_layerForScrollCorner)
         m_overflowControlsHostLayer->addChild(m_layerForScrollCorner.get());
 
     // The squashing containment layer, if it exists, becomes a no-op parent.
@@ skipping 1311 matching lines @@
     } else if (graphicsLayer == m_scrollingBlockSelectionLayer.get()) {
         name = "Scrolling Block Selection Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink