Add API for hit testing layer_impl touchEventHandlerRegions from the host

cc/layer_tree_host_common.h

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_LAYER_TREE_HOST_COMMON_H_
 #define CC_LAYER_TREE_HOST_COMMON_H_
 
 #include "base/memory/ref_counted.h"
 #include "cc/cc_export.h"
 #include "cc/scoped_ptr_vector.h"
@@ skipping 10 matching lines @@
 class CC_EXPORT LayerTreeHostCommon {
 public:
     static gfx::Rect calculateVisibleRect(const gfx::Rect& targetSurfaceRect, const gfx::Rect& layerBoundRect, const WebKit::WebTransformationMatrix&);
 
     static void calculateDrawTransforms(Layer* rootLayer, const gfx::Size& deviceViewportSize, float deviceScaleFactor, float pageScaleFactor, int maxTextureSize, std::vector<scoped_refptr<Layer> >& renderSurfaceLayerList);
     static void calculateDrawTransforms(LayerImpl* rootLayer, const gfx::Size& deviceViewportSize, float deviceScaleFactor, float pageScaleFactor, LayerSorter*, int maxTextureSize, std::vector<LayerImpl*>& renderSurfaceLayerList);
 
     // Performs hit testing for a given renderSurfaceLayerList.
     static LayerImpl* findLayerThatIsHitByPoint(const gfx::PointF& screenSpacePoint, std::vector<LayerImpl*>& renderSurfaceLayerList);
 
+    static LayerImpl* findLayerThatIsHitByPointInTouchHandlerRegion(const gfx::PointF& screenSpacePoint, std::vector<LayerImpl*>& renderSurfaceLayerList);
+
     template<typename LayerType> static bool renderSurfaceContributesToTarget(LayerType*, int targetSurfaceLayerID);
 
     // Returns a layer with the given id if one exists in the subtree starting
     // from the given root layer (including mask and replica layers).
     template<typename LayerType> static LayerType* findLayerInSubtree(LayerType* rootLayer, int layerId);
 
     static Layer* getChildAsRawPtr(const std::vector<scoped_refptr<Layer> >& children, size_t index)
     {
         return children[index].get();
     }
@@ skipping 46 matching lines @@
     for (size_t i = 0; i < rootLayer->children().size(); ++i) {
         if (LayerType* found = findLayerInSubtree(getChildAsRawPtr(rootLayer->children(), i), layerId))
             return found;
     }
     return 0;
 }
 
 }  // namespace cc
 
 #endif  // CC_LAYER_TREE_HOST_COMMON_H_