Fix crashes in AutomationInternalCustomBindings due to no v8 context.

chrome/renderer/extensions/automation_internal_custom_bindings.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/renderer/extensions/automation_internal_custom_bindings.h"
 
 #include "base/bind.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/values.h"
@@ skipping 455 matching lines @@
       [](v8::Isolate* isolate, v8::ReturnValue<v8::Value> result,
          ui::AXNode* node, const std::string& attribute_name) {
         std::string attr_value;
         if (!node->data().GetHtmlAttribute(attribute_name.c_str(), &attr_value))
           return;
 
         result.Set(v8::String::NewFromUtf8(isolate, attr_value.c_str()));
       });
 }
 
-AutomationInternalCustomBindings::~AutomationInternalCustomBindings() {
+AutomationInternalCustomBindings::~AutomationInternalCustomBindings() {}
+
+void AutomationInternalCustomBindings::Invalidate() {
+  ObjectBackedNativeHandler::Invalidate();
+
   if (message_filter_)
     message_filter_->Detach();
-  STLDeleteContainerPairSecondPointers(tree_id_to_tree_cache_map_.begin(),
-                                       tree_id_to_tree_cache_map_.end());
+
+  // Delete the TreeCaches quickly by first clearing their delegates so
+  // we don't get a callback for every node being deleted.
+  for (auto iter : tree_id_to_tree_cache_map_) {
+    TreeCache* cache = iter.second;
+    cache->tree.SetDelegate(nullptr);
+    delete cache;
+  }
+  tree_id_to_tree_cache_map_.clear();
 }
 
 void AutomationInternalCustomBindings::OnMessageReceived(
     const IPC::Message& message) {
   IPC_BEGIN_MESSAGE_MAP(AutomationInternalCustomBindings, message)
     IPC_MESSAGE_HANDLER(ExtensionMsg_AccessibilityEvent, OnAccessibilityEvent)
   IPC_END_MESSAGE_MAP()
 }
 
 TreeCache* AutomationInternalCustomBindings::GetTreeCacheFromTreeID(
@@ skipping 247 matching lines @@
   v8::HandleScope handle_scope(isolate);
   v8::Context::Scope context_scope(context()->v8_context());
   v8::Local<v8::Array> args(v8::Array::New(GetIsolate(), 3U));
   args->Set(0U, v8::Integer::New(GetIsolate(), tree_id));
   args->Set(1U, v8::Integer::New(GetIsolate(), node->id()));
   args->Set(2U, CreateV8String(isolate, ToString(change_type)));
   context()->DispatchEvent("automationInternal.onTreeChange", args);
 }
 
 }  // namespace extensions