Implement Wheel Gesture Scrolling on OSX.

content/renderer/mus/render_widget_mus_connection.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_MUS_RENDER_WIDGET_MUS_CONNECTION_H_
 #define CONTENT_RENDERER_MUS_RENDER_WIDGET_MUS_CONNECTION_H_
 
 #include "base/macros.h"
 #include "base/threading/thread_checker.h"
 #include "cc/output/output_surface.h"
@@ skipping 25 matching lines @@
 
   explicit RenderWidgetMusConnection(int routing_id);
   ~RenderWidgetMusConnection() override;
 
   // RenderWidgetInputHandlerDelegate implementation:
   void FocusChangeComplete() override;
   bool HasTouchEventHandlersAt(const gfx::Point& point) const override;
   void ObserveWheelEventAndResult(const blink::WebMouseWheelEvent& wheel_event,
                                   const gfx::Vector2dF& wheel_unused_delta,
                                   bool event_processed) override;
+  void ObserveGestureEventAndResult(const blink::WebGestureEvent& gesture_event,
+                                    const gfx::Vector2dF& gesture_unused_delta,
+                                    bool event_processed) override;
   void OnDidHandleKeyEvent() override;
   void OnDidOverscroll(const DidOverscrollParams& params) override;
   void OnInputEventAck(scoped_ptr<InputEventAck> input_event_ack) override;
   void NonBlockingInputEventHandled(
       blink::WebInputEvent::Type handled_type) override;
   void SetInputHandler(RenderWidgetInputHandler* input_handler) override;
   void UpdateTextInputState(ShowIme show_ime,
                             ChangeSource change_source) override;
   bool WillHandleGestureEvent(const blink::WebGestureEvent& event) override;
   bool WillHandleMouseEvent(const blink::WebMouseEvent& event) override;
@@ skipping 11 matching lines @@
 
   // Used to verify single threaded access.
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetMusConnection);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MUS_RENDER_WIDGET_MUS_CONNECTION_H_