Reland Ensure WebView notifies desktop automation on creation, destruction, and change

ui/views/accessibility/ax_aura_obj_cache.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 "ui/views/accessibility/ax_aura_obj_cache.h"
 
 #include "base/memory/singleton.h"
 #include "base/stl_util.h"
 #include "ui/aura/window.h"
 #include "ui/views/accessibility/ax_aura_obj_wrapper.h"
@@ skipping 58 matching lines @@
 void AXAuraObjCache::Remove(int32 id) {
   AXAuraObjWrapper* obj = Get(id);
 
   if (id == -1 || !obj)
     return;
 
   cache_.erase(id);
   delete obj;
 }
 
-AXAuraObjCache::AXAuraObjCache() : current_id_(1) {
+AXAuraObjCache::AXAuraObjCache() : current_id_(1), is_destroying_(false) {
 }
 
 AXAuraObjCache::~AXAuraObjCache() {
+  is_destroying_ = true;
   STLDeleteContainerPairSecondPointers(cache_.begin(), cache_.end());
   cache_.clear();
 }
 
 template <typename AuraViewWrapper, typename AuraView>
 AXAuraObjWrapper* AXAuraObjCache::CreateInternal(
     AuraView* aura_view, std::map<AuraView*, int32>& aura_view_to_id_map) {
   if (!aura_view)
     return NULL;
 
@@ skipping 28 matching lines @@
 void AXAuraObjCache::RemoveInternal(
     AuraView* aura_view, std::map<AuraView*, int32>& aura_view_to_id_map) {
   int32 id = GetID(aura_view);
   if (id == -1)
     return;
   aura_view_to_id_map.erase(aura_view);
   Remove(id);
 }
 
 }  // namespace views