Implement automatic load of composed/embedded automation trees

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 "base/stl_util.h"
+#include "ui/accessibility/ax_export.h"
+
+template <typename T>
+struct DefaultSingletonTraits;
+
+namespace ui {
+
+// A class which generates a unique id given a process id and routing id.
+// Currently, placeholder implementation pending finalization of out of process
+// iframes.
+class AX_EXPORT AXTreeIDRegistry {

[dmazzoni, 2014/10/31 22:20:26]

This class looks great, but it can't go in ui/accessibility.

Some options:

1) Put the interface in content/public/browser.
2) It's only used from chrome/ for now, so put it in
chrome/browser/accessibility; until in the future if native accessibility wants
to share these ids

[David Tseng, 2014/11/03 15:45:08]

Technically, no deps violations, but yeah, it should probably go under chrome/
or content/.

Putting under chrome/ for now until we figure out the situation with other
platforms.

+ public:
+  typedef int AXTreeID;
+  typedef std::pair<int, int> FrameID;
+
+  // 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.
+  int GetOrCreateAXTreeID(int process_id, int routing_id);
+  FrameID GetFrameID(int ax_tree_id);
+  void RemoveAXTreeID(int ax_tree_id);0
+
+ private:
+  friend struct DefaultSingletonTraits<AXTreeIDRegistry>;
+
+  AXTreeIDRegistry();
+  virtual ~AXTreeIDRegistry();
+
+  // Tracks the current unique ax frame id.
+  int 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_;
+
+  DISALLOW_COPY_AND_ASSIGN(AXTreeIDRegistry);
+};
+
+}  // namespace ui
+
+#endif  // UI_ACCESSIBILITY_AX_TREE_ID_REGISTRY_H_