Fix a few lingering bugs in BrowserAccessibilityManager and BrowserAccessibilityCocoa.

content/browser/accessibility/browser_accessibility_manager.cc

 // Copyright (c) 2011 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/browser_accessibility_manager.h"
 
 #include "base/logging.h"
 #include "content/browser/accessibility/browser_accessibility.h"
 #include "content/common/view_messages.h"
 
@@ skipping 17 matching lines @@
 BrowserAccessibilityManager* BrowserAccessibilityManager::Create(
     gfx::NativeView parent_view,
     const WebAccessibility& src,
     BrowserAccessibilityDelegate* delegate,
     BrowserAccessibilityFactory* factory) {
   return new BrowserAccessibilityManager(
       parent_view, src, delegate, factory);
 }
 #endif
 
+// static
+BrowserAccessibilityManager* BrowserAccessibilityManager::CreateEmptyDocument(
+    gfx::NativeView parent_view,
+    WebAccessibility::State state,
+    BrowserAccessibilityDelegate* delegate,
+    BrowserAccessibilityFactory* factory) {
+  // Use empty document to process notifications
+  webkit_glue::WebAccessibility empty_document;
+  // Renderer id's always start at 1000 as determined by webkit. Boot strap
+  // our ability to reuse BrowserAccessibility instances.
+  empty_document.id = 1000;
+  empty_document.role = WebAccessibility::ROLE_WEB_AREA;
+  empty_document.state = state;
+  return BrowserAccessibilityManager::Create(
+      parent_view, empty_document, delegate, factory);
+}
+
 BrowserAccessibilityManager::BrowserAccessibilityManager(
     gfx::NativeView parent_view,
     const WebAccessibility& src,
     BrowserAccessibilityDelegate* delegate,
     BrowserAccessibilityFactory* factory)
     : parent_view_(parent_view),
       delegate_(delegate),
       factory_(factory),
       focus_(NULL) {
   root_ = CreateAccessibilityTree(NULL, src, 0);
@@ skipping 44 matching lines @@
       renderer_id_to_child_id_map_.find(renderer_id);
   if (iter == renderer_id_to_child_id_map_.end())
     return NULL;
 
   int32 child_id = iter->second;
   return GetFromChildID(child_id);
 }
 
 void BrowserAccessibilityManager::Remove(int32 child_id, int32 renderer_id) {
   child_id_map_.erase(child_id);
-  renderer_id_to_child_id_map_.erase(renderer_id);
+  // Make sure we don't overwrite a newer entry (see UpdateNode for a possible
+  // corner case).
+  if (renderer_id_to_child_id_map_[renderer_id] == child_id)
+    renderer_id_to_child_id_map_.erase(renderer_id);
 }
 
 void BrowserAccessibilityManager::OnAccessibilityNotifications(
     const std::vector<ViewHostMsg_AccessibilityNotification_Params>& params) {
   for (uint32 index = 0; index < params.size(); index++) {
     const ViewHostMsg_AccessibilityNotification_Params& param = params[index];
 
     switch (param.notification_type) {
       case ViewHostMsg_AccessibilityNotification_Type::
           NOTIFICATION_TYPE_CHECK_STATE_CHANGED:
@@ skipping 64 matching lines @@
     NotifyAccessibilityEvent(
         ViewHostMsg_AccessibilityNotification_Type::
         NOTIFICATION_TYPE_FOCUS_CHANGED,
         focus_);
   }
 }
 
 void BrowserAccessibilityManager::OnAccessibilityObjectLoadComplete(
   const WebAccessibility& acc_obj) {
   SetFocus(NULL, false);
-  root_->InternalReleaseReference(true);
 
-  root_ = CreateAccessibilityTree(NULL, acc_obj, 0);
+  root_ = UpdateNode(acc_obj, true);
   if (!focus_)
     SetFocus(root_, false);
 
   NotifyAccessibilityEvent(
       ViewHostMsg_AccessibilityNotification_Type::
           NOTIFICATION_TYPE_LOAD_COMPLETE,
       root_);
   if (delegate_ && delegate_->HasFocus())
     GotFocus();
 }
@@ skipping 40 matching lines @@
 BrowserAccessibility* BrowserAccessibilityManager::GetFocus(
     BrowserAccessibility* root) {
   if (focus_ && (!root || focus_->IsDescendantOf(root)))
     return focus_;
 
   return NULL;
 }
 
 void BrowserAccessibilityManager::SetFocus(
     BrowserAccessibility* node, bool notify) {
-  if (focus_)
-    focus_->InternalReleaseReference(false);
-  focus_ = node;
-  if (focus_)
-    focus_->InternalAddReference();
+  if (focus_ != node) {
+    if (focus_)
+      focus_->InternalReleaseReference(false);
+    focus_ = node;
+    if (focus_)
+      focus_->InternalAddReference();
+  }
 
   if (notify && node && delegate_)
     delegate_->SetAccessibilityFocus(node->renderer_id());
 }
 
 void BrowserAccessibilityManager::DoDefaultAction(
     const BrowserAccessibility& node) {
   if (delegate_)
     delegate_->AccessibilityDoDefaultAction(node.renderer_id());
 }
@@ skipping 39 matching lines @@
   // Build a new tree, reusing old nodes if possible. Each node that's
   // reused will have its reference count incremented by one.
   current =
       CreateAccessibilityTree(current_parent, src, current_index_in_parent);
 
   // Decrement the reference count of all nodes in the old tree, which will
   // delete any nodes no longer needed.
   for (int i = 0; i < static_cast<int>(old_tree_nodes.size()); i++)
     old_tree_nodes[i]->InternalReleaseReference(false);
 
-  DCHECK(focus_);
-  if (!focus_->instance_active())
+  if (!focus_ || !focus_->instance_active())
     SetFocus(root_, false);
 
   return current;
 }
 
 BrowserAccessibility* BrowserAccessibilityManager::CreateAccessibilityTree(
     BrowserAccessibility* parent,
     const WebAccessibility& src,
     int index_in_parent) {
   BrowserAccessibility* instance = NULL;
@@ skipping 38 matching lines @@
   if ((src.state >> WebAccessibility::STATE_FOCUSED) & 1)
     SetFocus(instance, false);
   for (int i = 0; i < static_cast<int>(src.children.size()); ++i) {
     BrowserAccessibility* child = CreateAccessibilityTree(
         instance, src.children[i], i);
     instance->AddChild(child);
   }
 
   return instance;
 }