Update from https://crrev.com/328418

base/message_loop/message_loop_proxy_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 "base/message_loop/message_loop_proxy_impl.h"
 
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/message_loop/incoming_task_queue.h"
 #include "base/message_loop/message_loop.h"
 
 namespace base {
 namespace internal {
 
 MessageLoopProxyImpl::MessageLoopProxyImpl(
     scoped_refptr<IncomingTaskQueue> incoming_queue)
     : incoming_queue_(incoming_queue),
-      valid_thread_id_(PlatformThread::CurrentId()) {
+      valid_thread_id_(kInvalidThreadId) {
+}
+
+void MessageLoopProxyImpl::BindToCurrentThread() {
+  DCHECK_EQ(kInvalidThreadId, valid_thread_id_);
+  valid_thread_id_ = PlatformThread::CurrentId();
 }
 
 bool MessageLoopProxyImpl::PostDelayedTask(
     const tracked_objects::Location& from_here,
     const base::Closure& task,
     base::TimeDelta delay) {
   DCHECK(!task.is_null()) << from_here.ToString();
   return incoming_queue_->AddToIncomingQueue(from_here, task, delay, true);
 }
 
@@ skipping 16 matching lines @@
 
 scoped_refptr<MessageLoopProxy>
 MessageLoopProxy::current() {
   MessageLoop* cur_loop = MessageLoop::current();
   if (!cur_loop)
     return NULL;
   return cur_loop->message_loop_proxy();
 }
 
 }  // namespace base