Adding support for sending horizonatal mouse wheel information in Chrome ASH on Windows 8.

win8/metro_driver/chrome_app_view_ash.h

 // Copyright (c) 2012 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 WIN8_METRO_DRIVER_CHROME_APP_VIEW_ASH_H_
 #define WIN8_METRO_DRIVER_CHROME_APP_VIEW_ASH_H_
 
 #include <windows.applicationmodel.core.h>
 #include <windows.ui.core.h>
 #include <windows.ui.input.h>
@@ skipping 113 matching lines @@
       const std::vector<metro_viewer::UnderlineInfo>& underlines) OVERRIDE;
   virtual void OnTextCommitted(const base::string16& text) OVERRIDE;
 
   // Convenience for sending a MetroViewerHostMsg_MouseButton with the specified
   // parameters.
   void SendMouseButton(int x,
                        int y,
                        int extra,
                        ui::EventType event_type,
                        uint32 flags,
-                       ui::EventFlags changed_button);
+                       ui::EventFlags changed_button,
+                       bool is_horizontal_wheel);
 
   // Win8 only generates a mouse press for the initial button that goes down and
   // a release when the last button is released. Any intermediary presses (or
   // releases) do not result in a new press/release event. Instead a move is
   // generated with the winui::Input::PointerUpdateKind identifying what
   // changed. This function generates the necessary intermediary events (as
   // necessary).
   void GenerateMouseEventFromMoveIfNecessary(const PointerInfoHandler& pointer);
 
   HRESULT OnActivate(winapp::Core::ICoreApplicationView* view,
@@ skipping 75 matching lines @@
 
   // UI message loop to allow message passing into this thread.
   base::MessageLoopForUI ui_loop_;
 
   // For IME support.
   scoped_ptr<metro_driver::InputSource> input_source_;
   scoped_ptr<metro_driver::TextService> text_service_;
 };
 
 #endif  // WIN8_METRO_DRIVER_CHROME_APP_VIEW_ASH_H_