Implement ChildThread::shutdown and clear members that have refs into blink

content/utility/utility_thread_impl.cc

 // Copyright (c) 2012 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/utility/utility_thread_impl.h"
 
 #include <stddef.h>
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
@@ skipping 34 matching lines @@
 UtilityThreadImpl::UtilityThreadImpl(const std::string& channel_name)
     : ChildThread(channel_name),
       single_process_(true) {
   Init();
 }
 
 UtilityThreadImpl::~UtilityThreadImpl() {
 }
 
 void UtilityThreadImpl::Shutdown() {
+  ChildThread::Shutdown();
+
   if (!single_process_)
     WebKit::shutdown();
 }
 
 bool UtilityThreadImpl::Send(IPC::Message* msg) {
   return ChildThread::Send(msg);
 }
 
 void UtilityThreadImpl::ReleaseProcessIfNeeded() {
   if (batch_mode_)
@@ skipping 89 matching lines @@
       Send(new UtilityHostMsg_LoadPluginFailed(i, plugin_paths[i]));
     else
       Send(new UtilityHostMsg_LoadedPlugin(i, plugin));
   }
 
   ReleaseProcessIfNeeded();
 }
 #endif
 
 }  // namespace content