Initial support for accessibility actions on ARC.

ui/accessibility/ax_tree_id_registry.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_ACCESSIBILITY_AX_TREE_ID_REGISTRY_H_
 #define UI_ACCESSIBILITY_AX_TREE_ID_REGISTRY_H_
 
 #include <map>
 #include <utility>
 
 #include "base/macros.h"
 #include "ui/accessibility/ax_export.h"
 
 namespace base {
 template <typename T>
 struct DefaultSingletonTraits;
 }  // namespace base
 
 namespace ui {
 
-// A class which generates a unique id.
+class AXHostDelegate;
+
+// This class generates and saves a runtime id for an accessibility tree.
+// It provides a few distinct forms of generating an id:
+//     - from a frame id (which consists of a process and routing id)
+//     - from a backing object

[dmazzoni, 2017/02/20 04:50:46]

from a backing AXHostDelegate object

[David Tseng, 2017/02/21 19:09:05]

Done.

+//
+// The first form allows underlying instances to change but refer to the same
+// frame.
+// The second form allows this registry to track the object for later retrieval.
 class AX_EXPORT AXTreeIDRegistry {
  public:
   using FrameID = std::pair<int, int>;
 
   using AXTreeID = int;
 
   static const AXTreeID kNoAXTreeID;
 
   // Get the single instance of this class.
   static AXTreeIDRegistry* GetInstance();
 
-  // Obtains a unique id given a |process_id| and |routing_id|. Placeholder
-  // for full implementation once out of process iframe accessibility finalizes.
+  // Methods for FrameID ax tree id generation, and retrieval.
   AXTreeID GetOrCreateAXTreeID(int process_id, int routing_id);
   FrameID GetFrameID(AXTreeID ax_tree_id);
+
+  // Methods for AXHostDelegate ax tree id generation, and retrieval.
+  AXTreeID GetOrCreateAXTreeID(AXHostDelegate* delegate);
+  AXHostDelegate* GetHostDelegate(AXTreeID ax_tree_id);
+  void SetDesktopHostDelegate(AXHostDelegate* delegate);
+
   void RemoveAXTreeID(AXTreeID ax_tree_id);
 
-  // Create an id not associated with any process.
-  int CreateID();
-
  private:
   friend struct base::DefaultSingletonTraits<AXTreeIDRegistry>;
 
   AXTreeIDRegistry();
   virtual ~AXTreeIDRegistry();
 
   // Tracks the current unique ax frame id.
   AXTreeID ax_tree_id_counter_;
 
   // Maps an accessibility tree to its frame via ids.
   std::map<AXTreeID, FrameID> ax_tree_to_frame_id_map_;
 
   // Maps frames to an accessibility tree via ids.
   std::map<FrameID, AXTreeID> frame_to_ax_tree_id_map_;
 
+  // Maps an id to its host delegate.
+  std::map<AXTreeID, AXHostDelegate*> id_to_host_delegate_;
+
   DISALLOW_COPY_AND_ASSIGN(AXTreeIDRegistry);
 };
 
 }  // namespace ui
 
 #endif  // UI_ACCESSIBILITY_AX_TREE_ID_REGISTRY_H_