[ash-md] Corrects a crash when a window is destroyed after leaving overview

ash/common/wm/overview/window_selector_item.h

 // Copyright 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 ASH_COMMON_WM_OVERVIEW_WINDOW_SELECTOR_ITEM_H_
 #define ASH_COMMON_WM_OVERVIEW_WINDOW_SELECTOR_ITEM_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
 #include "ash/common/wm/overview/scoped_transform_overview_window.h"
 #include "ash/common/wm_window_observer.h"
 #include "base/macros.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/controls/button/image_button.h"
 #include "ui/views/controls/button/label_button.h"
 #include "ui/views/widget/widget.h"
 
+namespace gfx {
+class SlideAnimation;
+}
+
 namespace views {
 class ImageButton;
 }
 
 namespace wm {
 class Shadow;
 }
 
 namespace ash {
 
@@ skipping 163 matching lines @@
   // Animates opacity of the |transform_window_| and its caption to |opacity|
   // using |animation_type|.
   void AnimateOpacity(float opacity, OverviewAnimationType animation_type);
 
   // Updates the close buttons accessibility name.
   void UpdateCloseButtonAccessibilityName();
 
   // Fades out a window caption when exiting overview mode.
   void FadeOut(std::unique_ptr<views::Widget> widget);
 
+  // Allows a test to directly set animation state.
+  gfx::SlideAnimation* GetBackgroundViewAnimation();
+
   static bool hide_header() { return use_mask_ || use_shape_; }
 
   // True if the item is being shown in the overview, false if it's being
   // filtered.
   bool dimmed_;
 
   // The root window this item is being displayed on.
   WmWindow* root_window_;
 
   // The contained Window's wrapper.
@@ skipping 52 matching lines @@
   // shape. This has performance implications so it can be disabled when there
   // are many windows.
   static bool use_shape_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowSelectorItem);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_WM_OVERVIEW_WINDOW_SELECTOR_ITEM_H_