Shutdown renderer main message loop before blink::shutdown()

content/child/child_thread_impl.h

Index: content/child/child_thread_impl.h
diff --git a/content/child/child_thread_impl.h b/content/child/child_thread_impl.h
index ae2fa203fecd7d5fffb15ed5a2853d69887af8b1..d5865fbe1dee5926111413296ab8bd0d24a6b48f 100644
--- a/content/child/child_thread_impl.h
+++ b/content/child/child_thread_impl.h
@@ -192,6 +192,10 @@ class CONTENT_EXPORT ChildThreadImpl
 
   base::MessageLoop* message_loop() const { return message_loop_; }
 
+  base::SingleThreadTaskRunner* main_task_runner() const {
+    return main_task_runner_.get();
+  }
+
   // Returns the one child thread. Can only be called on the main thread.
   static ChildThreadImpl* current();
 
@@ -284,6 +288,8 @@ class CONTENT_EXPORT ChildThreadImpl
 
   base::MessageLoop* message_loop_;
 
+  scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
+
   std::unique_ptr<FileSystemDispatcher> file_system_dispatcher_;
 
   std::unique_ptr<QuotaDispatcher> quota_dispatcher_;