Update from https://crrev.com/328418

base/message_loop/message_loop_proxy_impl.h

Index: base/message_loop/message_loop_proxy_impl.h
diff --git a/base/message_loop/message_loop_proxy_impl.h b/base/message_loop/message_loop_proxy_impl.h
index 0fe629f9d140c0244128e49598308a9a48d15366..c477320dfb93d13190af7e9deb9ff7948fa368c5 100644
--- a/base/message_loop/message_loop_proxy_impl.h
+++ b/base/message_loop/message_loop_proxy_impl.h
@@ -24,6 +24,9 @@ class BASE_EXPORT MessageLoopProxyImpl : public MessageLoopProxy {
   explicit MessageLoopProxyImpl(
       scoped_refptr<IncomingTaskQueue> incoming_queue);
 
+  // Initialize this message loop proxy on the current thread.
+  void BindToCurrentThread();
+
   // MessageLoopProxy implementation
   bool PostDelayedTask(const tracked_objects::Location& from_here,
                        const base::Closure& task,