Update focus when widget changes visibility.

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 64 matching lines @@
 
   // 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();
 
+  // Send a notification that the focused view may have changed.
+  void OnFocusedViewChanged();
+
   // 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;
@@ skipping 34 matching lines @@
   bool is_destroying_;
 
   Delegate* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(AXAuraObjCache);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_ACCESSIBILITY_AX_AURA_OBJ_CACHE_H_