Reland 66791 (change was innocent)...

base/message_loop_proxy_impl.cc

 // Copyright (c) 2010 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_proxy_impl.h"
+#include "base/thread_restrictions.h"
 
 namespace base {
 
 MessageLoopProxyImpl::MessageLoopProxyImpl()
     : target_message_loop_(MessageLoop::current()) {
   target_message_loop_->AddDestructionObserver(this);
 }
 
 MessageLoopProxyImpl::~MessageLoopProxyImpl() {
   AutoLock lock(message_loop_lock_);
@@ skipping 22 matching lines @@
 }
 
 bool MessageLoopProxyImpl::PostNonNestableDelayedTask(
     const tracked_objects::Location& from_here,
     Task* task,
     int64 delay_ms) {
   return PostTaskHelper(from_here, task, delay_ms, false);
 }
 
 bool MessageLoopProxyImpl::BelongsToCurrentThread() {
+  // We shouldn't use MessageLoop::current() since it uses LazyInstance which
+  // may be deleted by ~AtExitManager when a WorkerPool thread calls this
+  // function.
+  // http://crbug.com/63678
+  base::ThreadRestrictions::ScopedAllowSingleton allow_singleton;
   AutoLock lock(message_loop_lock_);
   return (target_message_loop_ &&
           (MessageLoop::current() == target_message_loop_));
 }
 
 bool MessageLoopProxyImpl::PostTaskHelper(
     const tracked_objects::Location& from_here, Task* task, int64 delay_ms,
     bool nestable) {
   bool ret = false;
   {
@@ skipping 33 matching lines @@
   target_message_loop_ = NULL;
 }
 
 scoped_refptr<MessageLoopProxy>
 MessageLoopProxy::CreateForCurrentThread() {
   scoped_refptr<MessageLoopProxy> ret(new MessageLoopProxyImpl());
   return ret;
 }
 
 }  // namespace base
-