Implement initial support for nesting one ax tree in another.

content/browser/accessibility/frame_tree_accessibility.cc

+// Copyright (c) 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 "content/browser/accessibility/frame_tree_accessibility.h"
+
+namespace content {
+
+const uint32 kNoFrameId = 0;
+
+FrameTreeAccessibility::FrameTreeAccessibility()
+    : next_id_(1) {
+}
+
+FrameTreeAccessibility::~FrameTreeAccessibility() {
+}
+
+FrameTreeAccessibility* FrameTreeAccessibility::GetInstance() {
+  return Singleton<FrameTreeAccessibility>::get();
+}
+
+void FrameTreeAccessibility::OnFrameCreated(
+    BrowserAccessibilityDelegate* frame) {
+  uint32 id = next_id_++;
+  frame_to_id_[frame] = id;
+  id_to_frame_[id] = frame;
+}
+
+void FrameTreeAccessibility::OnFrameDeleted(
+    BrowserAccessibilityDelegate* frame) {
+  if (frame_to_id_.find(frame) == frame_to_id_.end())
+    return;
+  uint32 id = frame_to_id_[frame];
+  frame_to_id_.erase(frame);
+  id_to_frame_.erase(id);
+  id_to_manager_.erase(id);
+}
+
+void FrameTreeAccessibility::SetFrameAccessibilityManager(
+    BrowserAccessibilityDelegate* frame,
+    BrowserAccessibilityManager* manager) {
+  if (frame_to_id_.find(frame) == frame_to_id_.end())

[aboxhall, 2014/05/06 15:41:27]

How could this happen? Is it an error?

+    return;
+  uint32 id = frame_to_id_[frame];
+  id_to_manager_[id] = manager;
+}
+
+uint32 FrameTreeAccessibility::GetFrameId(BrowserAccessibilityDelegate* frame) {
+  if (frame_to_id_.find(frame) == frame_to_id_.end())
+    return kNoFrameId;
+  return frame_to_id_[frame];
+}
+
+BrowserAccessibilityDelegate* FrameTreeAccessibility::FindFrameById(uint32 id) {
+  if (id_to_frame_.find(id) == id_to_frame_.end())
+    return NULL;
+  return id_to_frame_[id];
+}
+
+BrowserAccessibilityManager*
+    FrameTreeAccessibility::FindAccessibilityManagerById(uint32 id) {
+  if (id_to_manager_.find(id) == id_to_manager_.end())
+    return NULL;
+  return id_to_manager_[id];
+}
+
+}  // namespace content