Fix RenderGeometryMap ASSERT in touch hit rect computation

Source/core/page/scrolling/ScrollingCoordinator.cpp

 /*
  * Copyright (C) 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 486 matching lines @@
                 layer = parentDocRenderer->enclosingLayer();
                 touchHandlerInChildFrame = true;
             }
         } while (layer);
     }
 
     // Now walk the layer projecting rects while maintaining a RenderGeometryMap
     MapCoordinatesFlags flags = UseTransforms;
     if (touchHandlerInChildFrame)
         flags |= TraverseDocumentBoundaries;
+    RenderLayer* rootLayer = mainFrame->contentRenderer()->layer();
     RenderGeometryMap geometryMap(flags);
+    geometryMap.pushMappingsToAncestor(rootLayer, 0);
     LayerFrameMap layerChildFrameMap;
     makeLayerChildFrameMap(mainFrame, &layerChildFrameMap);
-    convertLayerRectsToEnclosingCompositedLayerRecursive(mainFrame->contentRenderer()->layer(), layerRects, compositorRects, geometryMap, layersWithRects, layerChildFrameMap);
+    convertLayerRectsToEnclosingCompositedLayerRecursive(rootLayer, layerRects, compositorRects, geometryMap, layersWithRects, layerChildFrameMap);
 }
 
 void ScrollingCoordinator::updateTouchEventTargetRectsIfNeeded()
 {
     TRACE_EVENT0("input", "ScrollingCoordinator::updateTouchEventTargetRectsIfNeeded");
 
     if (!touchHitTestingEnabled())
         return;
 
     LayerHitTestRects touchEventTargetRects;
@@ skipping 429 matching lines @@
     bool frameIsScrollable = frameView && frameView->isScrollable();
     if (frameIsScrollable != m_wasFrameScrollable)
         return true;
 
     if (WebLayer* scrollLayer = frameView ? scrollingWebLayerForScrollableArea(frameView) : 0)
         return blink::WebSize(frameView->contentsSize()) != scrollLayer->bounds();
     return false;
 }
 
 } // namespace WebCore