Add DCHECK to BrowserAccessibilityManager::Remove to detect undefined behavoir that may lead to a...

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 98 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);
+
+  // TODO(ctguil): Investigate if hit. We should never have a newer entry.
+  DCHECK(renderer_id_to_child_id_map_[renderer_id] == child_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];
@@ skipping 255 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;
 }