Adds the option of aligning the launcher to the left or right. There

ash/launcher/launcher_button_host.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 ASH_LAUNCHER_LAUNCHER_BUTTON_HOST_H_
 #define ASH_LAUNCHER_LAUNCHER_BUTTON_HOST_H_
 #pragma once
 
 #include "ash/ash_export.h"
+#include "ash/wm/shelf_auto_hide_behavior.h"
 #include "base/string16.h"
 
 namespace views {
 class MouseEvent;
 class View;
 }
 
 namespace ash {
 namespace internal {
 
 // The launcher buttons communicate back to the host by way of this interface.
 // This interface is used to enable reordering the items on the launcher.
 class ASH_EXPORT LauncherButtonHost {
  public:
   // Invoked when the mose is pressed on a view.
   virtual void MousePressedOnButton(views::View* view,
                                     const views::MouseEvent& event) = 0;
 
   // Invoked when the mouse is dragged over a view.
   virtual void MouseDraggedOnButton(views::View* view,
                                     const views::MouseEvent& event) = 0;
 
   // Invoked either if the mouse is released or mouse capture canceled.
   virtual void MouseReleasedOnButton(views::View* view,
                                      bool canceled) = 0;
 
   // Invoked when the mouse exits the item.
   virtual void MouseExitedButton(views::View* view) = 0;
 
+  virtual ShelfAlignment GetShelfAlignment() const = 0;
+
   // Invoked to get the accessible name of the item.
   virtual string16 GetAccessibleName(const views::View* view) = 0;
 
  protected:
   virtual ~LauncherButtonHost() {}
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_LAUNCHER_LAUNCHER_BUTTON_HOST_H_