Index: message_loop.cc
===================================================================
--- message_loop.cc	(revision 85124)
+++ message_loop.cc	(working copy)
@@ -387,9 +387,13 @@
 }
 
 void MessageLoop::AssertIdle() const {
+  DCHECK(IsIdle());
+}
+
+bool MessageLoop::IsIdle() const {
   // We only check |incoming_queue_|, since we don't want to lock |work_queue_|.
   base::AutoLock lock(incoming_queue_lock_);
-  DCHECK(incoming_queue_.empty());
+  return incoming_queue_.empty();
 }
 
 //------------------------------------------------------------------------------
Index: message_loop.h
===================================================================
--- message_loop.h	(revision 85124)
+++ message_loop.h	(working copy)
@@ -351,6 +351,9 @@
   // Asserts that the MessageLoop is "idle".
   void AssertIdle() const;
 
+  // Returns true if the MessageLoop is "idle".
+  bool IsIdle() const;
+
 #if defined(OS_WIN)
   void set_os_modal_loop(bool os_modal_loop) {
     os_modal_loop_ = os_modal_loop;