Add API for hit testing layer_impl touchEventHandlerRegions from the host

cc/layer_tree_host_impl.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_IMPL_H_
 #define CC_LAYER_TREE_HOST_IMPL_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time.h"
@@ skipping 100 matching lines @@
 
     // InputHandlerClient implementation
     virtual InputHandlerClient::ScrollStatus scrollBegin(gfx::Point, InputHandlerClient::ScrollInputType) OVERRIDE;
     virtual void scrollBy(gfx::Point, gfx::Vector2d) OVERRIDE;
     virtual void scrollEnd() OVERRIDE;
     virtual void pinchGestureBegin() OVERRIDE;
     virtual void pinchGestureUpdate(float, gfx::Point) OVERRIDE;
     virtual void pinchGestureEnd() OVERRIDE;
     virtual void startPageScaleAnimation(gfx::Vector2d targetPosition, bool anchorPoint, float pageScale, base::TimeTicks startTime, base::TimeDelta duration) OVERRIDE;
     virtual void scheduleAnimation() OVERRIDE;
+    virtual bool haveTouchEventHandlersAt(const gfx::Point&) OVERRIDE;
 
     struct CC_EXPORT FrameData : public RenderPassSink {
         FrameData();
         ~FrameData();
 
         std::vector<gfx::Rect> occludingScreenSpaceRects;
         RenderPassList renderPasses;
         RenderPassIdHashMap renderPassesById;
         LayerList* renderSurfaceLayerList;
         LayerList willDrawLayers;
@@ skipping 222 matching lines @@
 
     size_t m_numImplThreadScrolls;
     size_t m_numMainThreadScrolls;
 
     DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYER_TREE_HOST_IMPL_H_