Pending tasks in a message loop should be deleted before shutting down Blink

content/renderer/renderer_main.cc

Index: content/renderer/renderer_main.cc
diff --git a/content/renderer/renderer_main.cc b/content/renderer/renderer_main.cc
index dbe40235cabb0ba7ed839f0017a08e2ae13e4570..a84030dc142de5914cd37a7f12347cfc5668a3b6 100644
--- a/content/renderer/renderer_main.cc
+++ b/content/renderer/renderer_main.cc
@@ -230,6 +230,12 @@ int RendererMain(const MainFunctionParams& parameters) {
       base::MessageLoop::current()->Run();
       TRACE_EVENT_END_ETW("RendererMain.START_MSG_LOOP", 0, 0);
     }
+
+    // Since the destructors of the pending tasks can touch Blink objects,
+    // we need to make sure that all pending tasks are deleted before
+    // shutting down Blink (Blink is shut down in the RenderProcessImpl's
+    // destructor).
+    main_message_loop.DeletePendingTasks();

[jamesr, 2014/09/22 14:38:04]

since you're deleting *all* pending tasks and not just Blink ones then you
definitely do not care about anything else running, so not lgtm.  You should
simply shut down the loop before shutting down blink

[haraken, 2014/09/22 15:54:18]

I'm not familiar with a message loop, but what's a common way to completely shut
down the main_message_loop here?

At first I tried something like:

scoped_ptr<base::MessageLoop> main_message_loop(new base::MessageLoop());  //
line 155
{
  ...;
  main_message_loop.reset();  // line 238
}

but it crashed chrome :-/

   }
   platform.PlatformUninitialize();
   TRACE_EVENT_END_ETW("RendererMain", 0, "");