Cleanup shelf initialization and observation.

ash/shell_observer.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_SHELL_OBSERVER_H_
 #define ASH_SHELL_OBSERVER_H_
 
 #include "ash/ash_export.h"
 #include "ash/system/user/login_status.h"
 
@@ skipping 23 matching lines @@
 
   // Invoked after a non-primary root window is created.
   virtual void OnRootWindowAdded(aura::Window* root_window) {}
 
   // Invoked after the shelf has been created for |root_window|.
   virtual void OnShelfCreatedForRootWindow(aura::Window* root_window) {}
 
   // Invoked when the shelf alignment in |root_window| is changed.
   virtual void OnShelfAlignmentChanged(aura::Window* root_window) {}
 
+  // Invoked when the shelf auto-hide behavior in |root_window| is changed.
+  virtual void OnShelfAutoHideBehaviorChanged(aura::Window* root_window) {}
+
   // Invoked when the projection touch HUD is toggled.
   virtual void OnTouchHudProjectionToggled(bool enabled) {}
 
   // Invoked when entering or exiting fullscreen mode in |root_window|.
   virtual void OnFullscreenStateChanged(bool is_fullscreen,
                                         aura::Window* root_window) {}
 
   // Called when the overview mode is about to be started (before the windows
   // get re-arranged).
   virtual void OnOverviewModeStarting() {}
@@ skipping 12 matching lines @@
   // Called at the end of Shell::Init.
   virtual void OnShellInitialized() {}
 
  protected:
   virtual ~ShellObserver() {}
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELL_OBSERVER_H_