Ensure that trackpad and trackpoint scrolling works on Windows desktop Aura with legacy trackpad dr…

ui/views/widget/desktop_aura/desktop_root_window_host_win.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 UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_ROOT_WINDOW_HOST_WIN_H_
 #define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_ROOT_WINDOW_HOST_WIN_H_
 
 #include "ui/aura/client/animation_host.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/views/views_export.h"
@@ skipping 192 matching lines @@
                                       WPARAM w_param,
                                       LPARAM l_param) OVERRIDE;
   virtual void HandleMenuLoop(bool in_menu_loop) OVERRIDE;
   virtual bool PreHandleMSG(UINT message,
                             WPARAM w_param,
                             LPARAM l_param,
                             LRESULT* result) OVERRIDE;
   virtual void PostHandleMSG(UINT message,
                              WPARAM w_param,
                              LPARAM l_param) OVERRIDE;
+  virtual bool HandleScrollEvent(const ui::ScrollEvent& event) OVERRIDE;
 
   Widget* GetWidget();
   const Widget* GetWidget() const;
   HWND GetHWND() const;
 
  private:
   void SetWindowTransparency();
 
   // Returns true if a modal window is active in the current root window chain.
   bool IsModalWindowActive() const;
@@ skipping 49 matching lines @@
   bool is_cursor_visible_;
 
   scoped_ptr<aura::client::ScopedTooltipDisabler> tooltip_disabler_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopWindowTreeHostWin);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_ROOT_WINDOW_HOST_WIN_H_