[ash-md] Adjusts animation of the selector after closing an overview item

ash/common/wm/overview/window_grid.h

Index: ash/common/wm/overview/window_grid.h
diff --git a/ash/common/wm/overview/window_grid.h b/ash/common/wm/overview/window_grid.h
index 9a3202713b1ca00068b75b07b4e43f7736490e9c..04b8b9e150c393b8e445aca3354bd5625f32b183 100644
--- a/ash/common/wm/overview/window_grid.h
+++ b/ash/common/wm/overview/window_grid.h
@@ -91,6 +91,11 @@ class ASH_EXPORT WindowGrid : public WmWindowObserver {
   // If |pattern| is empty, no item is dimmed.
   void FilterItems(const base::string16& pattern);
 
+  // Called when |window| is about to get closed. If the |window| is currently
+  // selected the implementation fades out |selection_widget_| to transparent
+  // opacity, effectively hiding the selector widget.
+  void WindowClosing(WindowSelectorItem* window);
+
   // Returns true if the grid has no more windows.
   bool empty() const { return window_list_.empty(); }