Reland 66791 (change was innocent)...

base/message_loop_proxy_impl.cc

Index: base/message_loop_proxy_impl.cc
===================================================================
--- base/message_loop_proxy_impl.cc	(revision 66806)
+++ base/message_loop_proxy_impl.cc	(working copy)
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "base/message_loop_proxy_impl.h"
+#include "base/thread_restrictions.h"
 
 namespace base {
 
@@ -45,6 +46,11 @@
 }
 
 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_));
@@ -98,4 +104,3 @@
 }
 
 }  // namespace base
-