Fix virtual keyboard overscroll on Athena

ui/keyboard/keyboard_controller.h

Index: ui/keyboard/keyboard_controller.h
diff --git a/ui/keyboard/keyboard_controller.h b/ui/keyboard/keyboard_controller.h
index 7a7b41a74b7254df2064c5f916b25b416abf724f..49e50ed8da77291cb07b55f900719dc2bf4520af 100644
--- a/ui/keyboard/keyboard_controller.h
+++ b/ui/keyboard/keyboard_controller.h
@@ -27,9 +27,9 @@ class TextInputClient;
 namespace keyboard {
 
 class CallbackAnimationObserver;
-class WindowBoundsChangeObserver;
 class KeyboardControllerObserver;
 class KeyboardControllerProxy;
+class WindowBoundsChangeObserver;
 
 // Animation distance.
 const int kAnimationDistance = 30;
@@ -140,18 +140,15 @@ class KEYBOARD_EXPORT KeyboardController : public ui::InputMethodObserver,
   void ShowAnimationFinished();
   void HideAnimationFinished();
 
-  // 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);
-
   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_;
+  // Tracks changes to the root window's size while the keyboard is displayed
+  // (e.g. due to screen rotation).
+  scoped_ptr<WindowBoundsChangeObserver> root_window_bounds_observer_;
 
   ui::InputMethod* input_method_;
   bool keyboard_visible_;