Shutdown renderer main message loop before blink::shutdown()

content/child/child_thread_impl.cc

Index: content/child/child_thread_impl.cc
diff --git a/content/child/child_thread_impl.cc b/content/child/child_thread_impl.cc
index 6f7360358daae3d50a0eaaa168e18618227b1be3..7bede89965a056502c58608b854e5f356f6fae3b 100644
--- a/content/child/child_thread_impl.cc
+++ b/content/child/child_thread_impl.cc
@@ -402,6 +402,7 @@ void ChildThreadImpl::Init(const Options& options) {
   g_lazy_tls.Pointer()->Set(this);
   on_channel_error_called_ = false;
   message_loop_ = base::MessageLoop::current();
+  main_task_runner_ = message_loop_->task_runner();
 #ifdef IPC_MESSAGE_LOG_ENABLED
   // We must make sure to instantiate the IPC Logger *before* we create the
   // channel, otherwise we can get a callback on the IO thread which creates
@@ -464,7 +465,7 @@ void ChildThreadImpl::Init(const Options& options) {
 
   sync_message_filter_ = channel_->CreateSyncMessageFilter();
   thread_safe_sender_ = new ThreadSafeSender(
-      message_loop_->task_runner(), sync_message_filter_.get());
+      main_task_runner_, sync_message_filter_.get());
 
   resource_dispatcher_.reset(new ResourceDispatcher(
       this, message_loop()->task_runner()));
@@ -537,7 +538,7 @@ void ChildThreadImpl::Init(const Options& options) {
       connection_timeout = temp;
   }
 
-  message_loop_->task_runner()->PostDelayedTask(
+  main_task_runner_->PostDelayedTask(
       FROM_HERE, base::Bind(&ChildThreadImpl::EnsureConnected,
                             channel_connected_factory_->GetWeakPtr()),
       base::TimeDelta::FromSeconds(connection_timeout));
@@ -586,6 +587,7 @@ void ChildThreadImpl::Shutdown() {
   file_system_dispatcher_.reset();
   quota_dispatcher_.reset();
   WebFileSystemImpl::DeleteThreadSpecificInstance();
+  message_loop_ = nullptr;
 }
 
 void ChildThreadImpl::ShutdownDiscardableSharedMemoryManager() {
@@ -602,7 +604,7 @@ void ChildThreadImpl::OnChannelError() {
 }
 
 bool ChildThreadImpl::Send(IPC::Message* msg) {
-  DCHECK(message_loop_->task_runner()->BelongsToCurrentThread());
+  DCHECK(main_task_runner_->BelongsToCurrentThread());
   if (!channel_) {
     delete msg;
     return false;
@@ -649,13 +651,13 @@ shell::InterfaceProvider* ChildThreadImpl::GetRemoteInterfaces() {
 }
 
 IPC::MessageRouter* ChildThreadImpl::GetRouter() {
-  DCHECK(message_loop_->task_runner()->BelongsToCurrentThread());
+  DCHECK(main_task_runner_->BelongsToCurrentThread());
   return &router_;
 }
 
 std::unique_ptr<base::SharedMemory> ChildThreadImpl::AllocateSharedMemory(
     size_t buf_size) {
-  DCHECK(message_loop_->task_runner()->BelongsToCurrentThread());
+  DCHECK(main_task_runner_->BelongsToCurrentThread());
   return AllocateSharedMemory(buf_size, this, nullptr);
 }