Fix the issue that GetFrameWindow() may change between AddObserver and RemoveObserver in KeyboardCo…

ui/keyboard/keyboard_controller.h

 // Copyright (c) 2013 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_KEYBOARD_KEYBOARD_CONTROLLER_H_
 #define UI_KEYBOARD_KEYBOARD_CONTROLLER_H_
 
 #include "base/basictypes.h"
 #include "base/event_types.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 121 matching lines @@
   void ResetWindowInsets();
 
   // Returns true if keyboard is scheduled to hide.
   bool WillHideKeyboard() const;
 
   // Called when show and hide animation finished successfully. If the animation
   // is aborted, it won't be called.
   void ShowAnimationFinished();
   void HideAnimationFinished();
 
-  // Adds or removes an observer for tracking changes to a window size or
+  // Adds an observer for tracking changes to a window size or
   // position while the keyboard is displayed. Any window repositioning
   // invalidates insets for overscrolling.
   void AddBoundsChangedObserver(aura::Window* window);
-  void RemoveBoundsChangedObserver(aura::Window* window);
 
   scoped_ptr<KeyboardControllerProxy> proxy_;
   scoped_ptr<aura::Window> container_;
   // CallbackAnimationObserver should destructed before container_ because it
   // uses container_'s animator.
   scoped_ptr<CallbackAnimationObserver> animation_observer_;
 
   scoped_ptr<WindowBoundsChangeObserver> window_bounds_observer_;
 
   ui::InputMethod* input_method_;
@@ skipping 10 matching lines @@
   gfx::Rect current_keyboard_bounds_;
 
   static KeyboardController* instance_;
 
   DISALLOW_COPY_AND_ASSIGN(KeyboardController);
 };
 
 }  // namespace keyboard
 
 #endif  // UI_KEYBOARD_KEYBOARD_CONTROLLER_H_