Add API for hit testing layer_impl touchEventHandlerRegions from the host

cc/input_handler.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_INPUT_HANDLER_H_
 #define CC_INPUT_HANDLER_H_
 
 #include "base/basictypes.h"
 #include "base/time.h"
 #include "cc/cc_export.h"
 
 namespace gfx {
 class Point;
+class PointF;
 class Vector2d;
 }
 
 namespace cc {
 
 // The InputHandler is a way for the embedders to interact with
 // the impl thread side of the compositor implementation.
 //
 // There is one InputHandler for every LayerTreeHost. It is
 // created on the main thread and used only on the impl thread.
@@ skipping 31 matching lines @@
 
     virtual void startPageScaleAnimation(gfx::Vector2d targetOffset,
                                          bool anchorPoint,
                                          float pageScale,
                                          base::TimeTicks startTime,
                                          base::TimeDelta duration) = 0;
 
     // Request another callback to InputHandler::animate().
     virtual void scheduleAnimation() = 0;
 
+    virtual bool haveTouchEventHandlersAt(const gfx::Point&) = 0;
+
 protected:
     InputHandlerClient() { }
     virtual ~InputHandlerClient() { }
 
 private:
     DISALLOW_COPY_AND_ASSIGN(InputHandlerClient);
 };
 
 class CC_EXPORT InputHandler {
 public:
     virtual ~InputHandler() { }
 
     virtual void bindToClient(InputHandlerClient*) = 0;
     virtual void animate(base::TimeTicks time) = 0;
 
 protected:
     InputHandler() { }
 
 private:
     DISALLOW_COPY_AND_ASSIGN(InputHandler);
 };
 
 }
 
 #endif  // CC_INPUT_HANDLER_H_