Add Mojo API for Blink hit testing

content/renderer/input/render_widget_input_handler.h

 // Copyright 2015 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 CONTENT_RENDERER_INPUT_RENDER_WIDGET_INPUT_HANDLER_H_
 #define CONTENT_RENDERER_INPUT_RENDER_WIDGET_INPUT_HANDLER_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 20 matching lines @@
 class RenderWidgetInputHandlerDelegate;
 
 // RenderWidgetInputHandler is an IPC-agnostic input handling class.
 // IPC transport code should live in RenderWidget or RenderWidgetMusConnection.
 class CONTENT_EXPORT RenderWidgetInputHandler {
  public:
   RenderWidgetInputHandler(RenderWidgetInputHandlerDelegate* delegate,
                            RenderWidget* widget);
   virtual ~RenderWidgetInputHandler();
 
+  // Hit test the given point to find out the frame underneath.
+  int HitTestFrameAt(const gfx::Point& point);
+
   // Handle input events from the input event provider.
   virtual void HandleInputEvent(
       const blink::WebCoalescedInputEvent& coalesced_event,
       const ui::LatencyInfo& latency_info,
       HandledEventCallback callback);
 
   // Handle overscroll from Blink.
   void DidOverscrollFromBlink(
       const blink::WebFloatSize& overscrollDelta,
       const blink::WebFloatSize& accumulatedOverscroll,
@@ skipping 28 matching lines @@
 
   // Indicates if the next sequence of Char events should be suppressed or not.
   bool suppress_next_char_events_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetInputHandler);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_INPUT_RENDER_WIDGET_INPUT_HANDLER_H_