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 <set>
+
 #include "base/basictypes.h"
 #include "base/event_types.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
 #include "ui/aura/window_observer.h"
 #include "ui/base/ime/input_method_observer.h"
 #include "ui/base/ime/text_input_type.h"
 #include "ui/gfx/rect.h"
 #include "ui/keyboard/keyboard_export.h"
 #include "url/gurl.h"
@@ skipping 128 matching lines @@
   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_;
 
+  std::set<aura::Window*> observed_windows_;
+
   ui::InputMethod* input_method_;
   bool keyboard_visible_;
   bool show_on_resize_;
   bool lock_keyboard_;
   ui::TextInputType type_;
 
   ObserverList<KeyboardControllerObserver> observer_list_;
 
   base::WeakPtrFactory<KeyboardController> weak_factory_;
 
   // The currently used keyboard position.
   gfx::Rect current_keyboard_bounds_;
 
   static KeyboardController* instance_;
 
   DISALLOW_COPY_AND_ASSIGN(KeyboardController);
 };
 
 }  // namespace keyboard
 
 #endif  // UI_KEYBOARD_KEYBOARD_CONTROLLER_H_