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

content/plugin/plugin_thread.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/plugin/plugin_thread.h"
 
 #include "build/build_config.h"
 
 #if defined(TOOLKIT_GTK)
 #include <gtk/gtk.h>
@@ skipping 121 matching lines @@
 }
 
 PluginThread::~PluginThread() {
 }
 
 void PluginThread::SetForcefullyTerminatePluginProcess() {
   forcefully_terminate_plugin_process_ = true;
 }
 
 void PluginThread::Shutdown() {
+  ChildThread::Shutdown();
+
   if (preloaded_plugin_module_) {
     base::UnloadNativeLibrary(preloaded_plugin_module_);
     preloaded_plugin_module_ = NULL;
   }
   NPChannelBase::CleanupChannels();
   PluginLib::UnloadAllPlugins();
 
   if (forcefully_terminate_plugin_process_)
     base::KillProcess(base::GetCurrentProcessHandle(), 0, /* wait= */ false);
 
@@ skipping 31 matching lines @@
   }
 
   Send(new PluginProcessHostMsg_ChannelCreated(channel_handle));
 }
 
 void PluginThread::OnNotifyRenderersOfPendingShutdown() {
   PluginChannel::NotifyRenderersOfPendingShutdown();
 }
 
 }  // namespace content