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

content/gpu/gpu_child_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/gpu/gpu_child_thread.h"
 
 #include "base/bind.h"
 #include "base/lazy_instance.h"
 #include "base/threading/worker_pool.h"
 #include "build/build_config.h"
@@ skipping 59 matching lines @@
   if (!gfx::GLSurface::InitializeOneOff()) {
     VLOG(1) << "gfx::GLSurface::InitializeOneOff()";
   }
   g_thread_safe_sender.Get() = thread_safe_sender();
 }
 
 GpuChildThread::~GpuChildThread() {
 }
 
 void GpuChildThread::Shutdown() {
+  ChildThread::Shutdown();
   logging::SetLogMessageHandler(NULL);
 }
 
 void GpuChildThread::Init(const base::Time& process_start_time) {
   process_start_time_ = process_start_time;
 }
 
 bool GpuChildThread::Send(IPC::Message* msg) {
   // The GPU process must never send a synchronous IPC message to the browser
   // process. This could result in deadlock.
@@ skipping 140 matching lines @@
     // the future posting of tasks to the message loop.
     if (watchdog_thread_->message_loop())
       watchdog_thread_->PostAcknowledge();
     // Prevent rearming.
     watchdog_thread_->Stop();
   }
 }
 
 }  // namespace content