aura: Implement app list M19 mock.

ash/app_list/app_list.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_APP_LIST_APP_LIST_H_
 #define ASH_APP_LIST_APP_LIST_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "ui/aura/event_filter.h"
+#include "ui/aura/root_window_observer.h"
 #include "ui/gfx/compositor/layer_animation_observer.h"
 #include "ui/views/widget/widget.h"
 
 namespace ash {
 namespace internal {
 
 // AppList is a controller that manages app list UI for shell. To show the UI,
 // it requests app list widget from ShellDelegate and shows it when ready.
 // While the UI is visible, it monitors things such as app list widget's
 // activation state and desktop mouse click to auto dismiss the UI.
 class AppList : public aura::EventFilter,
+                public aura::RootWindowObserver,
                 public ui::ImplicitAnimationObserver,
                 public views::Widget::Observer {
  public:
   AppList();
   virtual ~AppList();
 
   // Show/hide app list window.
   void SetVisible(bool visible);
 
   // Whether app list window is visible (shown or being shown).
@@ skipping 14 matching lines @@
   virtual bool PreHandleKeyEvent(aura::Window* target,
                                  aura::KeyEvent* event) OVERRIDE;
   virtual bool PreHandleMouseEvent(aura::Window* target,
                                    aura::MouseEvent* event) OVERRIDE;
   virtual ui::TouchStatus PreHandleTouchEvent(aura::Window* target,
                                               aura::TouchEvent* event) OVERRIDE;
   virtual ui::GestureStatus PreHandleGestureEvent(
       aura::Window* target,
       aura::GestureEvent* event) OVERRIDE;
 
+  // aura::RootWindowObserver overrides:
+  virtual void OnRootWindowResized(const gfx::Size& new_size) OVERRIDE;
+
   // ui::ImplicitAnimationObserver overrides:
   virtual void OnImplicitAnimationsCompleted() OVERRIDE;
 
   // views::Widget::Observer overrides:
   virtual void OnWidgetClosing(views::Widget* widget) OVERRIDE;
   virtual void OnWidgetActivationChanged(views::Widget* widget,
       bool active) OVERRIDE;
 
   // Whether we should show or hide app list widget.
   bool is_visible_;
 
   // App list widget we get from ShellDelegate.
   views::Widget* widget_;
 
   DISALLOW_COPY_AND_ASSIGN(AppList);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  //  ASH_APP_LIST_APP_LIST_H_