Keep track of accessibility focus across windows.

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>
 #include <vector>
 
 #include "base/macros.h"
+#include "ui/aura/client/focus_change_observer.h"
 #include "ui/views/views_export.h"
 
 namespace base {
 template <typename T> struct DefaultSingletonTraits;
 }
 
 namespace aura {
+namespace client {
+class FocusClient;
+}
 class Window;
 }  // namespace aura
 
 namespace views {
 class AXAuraObjWrapper;
 class View;
 class Widget;
 
 // A cache responsible for assigning id's to a set of interesting Aura views.
-class VIEWS_EXPORT AXAuraObjCache {
+class VIEWS_EXPORT AXAuraObjCache
+    : public aura::client::FocusChangeObserver {
  public:
   // Get the single instance of this class.
   static AXAuraObjCache* GetInstance();
 
   // 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.
@@ skipping 15 matching lines @@
 
   // 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_; }
 
  private:
   friend struct base::DefaultSingletonTraits<AXAuraObjCache>;
 
   AXAuraObjCache();
-  virtual ~AXAuraObjCache();
+  ~AXAuraObjCache() override;
+
+  View* GetFocusedView();
+
+  // aura::client::FocusChangeObserver override.
+  void OnWindowFocused(aura::Window* gained_focus,
+                       aura::Window* lost_focus) override;
 
   template <typename AuraViewWrapper, typename AuraView>
   AXAuraObjWrapper* CreateInternal(
       AuraView* aura_view,
       std::map<AuraView*, int32_t>& aura_view_to_id_map);
 
   template <typename AuraView>
   int32_t GetIDInternal(AuraView* aura_view,
                         std::map<AuraView*, int32_t>& aura_view_to_id_map);
 
   template <typename AuraView>
   void RemoveInternal(AuraView* aura_view,
                       std::map<AuraView*, int32_t>& aura_view_to_id_map);
 
   std::map<views::View*, int32_t> view_to_id_map_;
   std::map<views::Widget*, int32_t> widget_to_id_map_;
   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_;
 
   DISALLOW_COPY_AND_ASSIGN(AXAuraObjCache);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_ACCESSIBILITY_AX_AURA_OBJ_CACHE_H_