Fix white virtual keyboard at login screen

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 38 matching lines @@
 
   // Returns the container for the keyboard, which is owned by
   // KeyboardController.
   aura::Window* GetContainerWindow();
 
   // Whether the container window for the keyboard has been initialized.
   bool keyboard_container_initialized() const {
     return container_.get() != NULL;
   }
 
-  // Reloads the content of the keyboard.
+  // Reloads the content of the keyboard. No-op if the keyboard content is not
+  // loaded yet.
   void Reload();
 
   // Hides virtual keyboard and notifies observer bounds change.
   // This function should be called with a delay to avoid layout flicker
   // when the focus of input field quickly change. |automatic| is true when the
   // call is made by the system rather than initiated by the user.
   void HideKeyboard(HideReason reason);
 
   // Notifies the keyboard observer for keyboard bounds changed.
   void NotifyKeyboardBoundsChanging(const gfx::Rect& new_bounds);
@@ skipping 78 matching lines @@
   gfx::Rect current_keyboard_bounds_;
 
   static KeyboardController* instance_;
 
   DISALLOW_COPY_AND_ASSIGN(KeyboardController);
 };
 
 }  // namespace keyboard
 
 #endif  // UI_KEYBOARD_KEYBOARD_CONTROLLER_H_