Update desktop tree when Aura windows are removed.

ui/views/accessibility/ax_aura_obj_cache.h

 // Copyright 2014 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_VIEWS_ACCESSIBILITY_AX_AURA_OBJ_CACHE_H_
 #define UI_VIEWS_ACCESSIBILITY_AX_AURA_OBJ_CACHE_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 21 matching lines @@
 class Widget;
 
 // A cache responsible for assigning id's to a set of interesting Aura views.
 class VIEWS_EXPORT AXAuraObjCache
     : public aura::client::FocusChangeObserver,
       public aura::WindowObserver {
  public:
   // Get the single instance of this class.
   static AXAuraObjCache* GetInstance();
 
+  class Delegate {
+   public:
+    virtual void OnChildWindowRemoved(AXAuraObjWrapper* parent) = 0;
+  };
+
   // Get or create an entry in the cache based on an Aura view.
   AXAuraObjWrapper* GetOrCreate(View* view);
   AXAuraObjWrapper* GetOrCreate(Widget* widget);
   AXAuraObjWrapper* GetOrCreate(aura::Window* window);
 
   // Gets an id given an Aura view.
   int32_t GetID(View* view) const;
   int32_t GetID(Widget* widget) const;
   int32_t GetID(aura::Window* window) const;
 
   // Gets the next unique id for this cache. Useful for non-Aura view backed
   // views.
   int32_t GetNextID() { return current_id_++; }
 
   // Removes an entry from this cache based on an Aura view.
   void Remove(View* view);
   void Remove(Widget* widget);
-  void Remove(aura::Window* window);
+
+  // Removes |window| and optionally notifies delegate by sending an event on
+  // the |parent| if provided.
+  void Remove(aura::Window* window, aura::Window* parent);
 
   // Removes a view and all of its descendants from the cache.
   void RemoveViewSubtree(View* view);
 
   // Lookup a cached entry based on an id.
   AXAuraObjWrapper* Get(int32_t id);
 
   // Remove a cached entry based on an id.
   void Remove(int32_t id);
 
   // Get all top level windows this cache knows about.
   void GetTopLevelWindows(std::vector<AXAuraObjWrapper*>* children);
 
   // Get the object that has focus.
   AXAuraObjWrapper* GetFocus();
 
   // Indicates if this object's currently being destroyed.
   bool is_destroying() { return is_destroying_; }
 
+  void SetDelegate(Delegate* delegate) { delegate_ = delegate; }
+
  private:
   friend struct base::DefaultSingletonTraits<AXAuraObjCache>;
 
   AXAuraObjCache();
   ~AXAuraObjCache() override;
 
   View* GetFocusedView();
 
   // aura::client::FocusChangeObserver override.
   void OnWindowFocused(aura::Window* gained_focus,
@@ skipping 21 matching lines @@
   std::map<aura::Window*, int32_t> window_to_id_map_;
 
   std::map<int32_t, AXAuraObjWrapper*> cache_;
   int32_t current_id_;
 
   aura::client::FocusClient* focus_client_;
 
   // True immediately when entering this object's destructor.
   bool is_destroying_;
 
+  Delegate* delegate_;
+
   DISALLOW_COPY_AND_ASSIGN(AXAuraObjCache);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_ACCESSIBILITY_AX_AURA_OBJ_CACHE_H_