Implement automatic load of composed/embedded automation trees

chrome/browser/accessibility/ax_tree_id_registry.cc

+// 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.
+
+#include "chrome/browser/accessibility/ax_tree_id_registry.h"
+
+#include "base/memory/singleton.h"
+
+// static
+AXTreeIDRegistry* AXTreeIDRegistry::GetInstance() {
+  return Singleton<AXTreeIDRegistry>::get();
+}
+
+int AXTreeIDRegistry::GetOrCreateAXTreeID(int process_id, int routing_id) {
+  FrameID frame_id(process_id, routing_id);
+  std::map<FrameID, AXTreeID>::iterator it;
+  it = frame_to_ax_tree_id_map_.find(frame_id);
+  if (it != frame_to_ax_tree_id_map_.end())
+    return it->second;
+
+  int new_id = ++ax_tree_id_counter_;
+  frame_to_ax_tree_id_map_[frame_id] = new_id;
+  ax_tree_to_frame_id_map_[new_id] = frame_id;
+
+  return new_id;
+}
+
+AXTreeIDRegistry::FrameID AXTreeIDRegistry::GetFrameID(int ax_tree_id) {
+  std::map<AXTreeID, FrameID>::iterator it;
+  it = ax_tree_to_frame_id_map_.find(ax_tree_id);
+  if (it != ax_tree_to_frame_id_map_.end())
+    return it->second;
+
+  return FrameID(-1, -1);
+}
+
+void AXTreeIDRegistry::RemoveAXTreeID(int ax_tree_id) {
+  std::map<AXTreeID, FrameID>::iterator it;
+  it = ax_tree_to_frame_id_map_.find(ax_tree_id);
+  if (it != ax_tree_to_frame_id_map_.end()) {
+    frame_to_ax_tree_id_map_.erase(it->second);
+    ax_tree_to_frame_id_map_.erase(it);
+  }
+}
+
+AXTreeIDRegistry::AXTreeIDRegistry() : ax_tree_id_counter_(-1) {
+  // Always populate default desktop tree value (0 -> 0, 0).
+  GetOrCreateAXTreeID(0, 0);
+}
+
+AXTreeIDRegistry::~AXTreeIDRegistry() {
+}