Initial support for accessibility actions on ARC.

ui/accessibility/ax_tree_id_registry.h

Index: ui/accessibility/ax_tree_id_registry.h
diff --git a/ui/accessibility/ax_tree_id_registry.h b/ui/accessibility/ax_tree_id_registry.h
index 7c16405e6836825f1bc9767b950a64fc30e88658..c6994485b862d9320c151ab9b76d6af3d2de98b9 100644
--- a/ui/accessibility/ax_tree_id_registry.h
+++ b/ui/accessibility/ax_tree_id_registry.h
@@ -18,7 +18,16 @@ struct DefaultSingletonTraits;
 
 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>;
@@ -30,14 +39,16 @@ class AX_EXPORT AXTreeIDRegistry {
   // 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);
-  void RemoveAXTreeID(AXTreeID ax_tree_id);
 
-  // Create an id not associated with any process.
-  int CreateID();
+  // 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);
 
  private:
   friend struct base::DefaultSingletonTraits<AXTreeIDRegistry>;
@@ -54,6 +65,9 @@ class AX_EXPORT AXTreeIDRegistry {
   // 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);
 };