ash: Start/stop observing KeyboardController via ShellObserver

ash/shell.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_H_
 #define ASH_SHELL_H_
 
 #include <memory>
 #include <utility>
 #include <vector>
@@ skipping 444 matching lines @@
   // Notifies observers that overview mode has ended.
   void NotifyOverviewModeEnded();
 
   // Notifies observers that fullscreen mode has changed for |root_window|.
   void NotifyFullscreenStateChanged(bool is_fullscreen, WmWindow* root_window);
 
   // Notifies observers that |pinned_window| changed its pinned window state.
   void NotifyPinnedStateChanged(WmWindow* pinned_window);
 
   // Notifies observers that the virtual keyboard has been
-  // activated/deactivated.
-  void NotifyVirtualKeyboardActivated(bool activated);
+  // activated/deactivated for |root_window|.
+  void NotifyVirtualKeyboardActivated(bool activated, WmWindow* root_window);
 
   // Notifies observers that the shelf was created for |root_window|.
   // TODO(jamescook): Move to Shelf.
   void NotifyShelfCreatedForRootWindow(WmWindow* root_window);
 
   // Notifies observers that |root_window|'s shelf changed alignment.
   // TODO(jamescook): Move to Shelf.
   void NotifyShelfAlignmentChanged(WmWindow* root_window);
 
   // Notifies observers that |root_window|'s shelf changed auto-hide behavior.
@@ skipping 178 matching lines @@
   base::ObserverList<ShellObserver> shell_observers_;
 
   scoped_refptr<base::SequencedWorkerPool> blocking_pool_;
 
   DISALLOW_COPY_AND_ASSIGN(Shell);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELL_H_