Never lock the Pepper proxy lock on the IO thread

ppapi/proxy/resource_reply_thread_registrar.cc

Index: ppapi/proxy/resource_reply_thread_registrar.cc
diff --git a/ppapi/proxy/resource_reply_thread_registrar.cc b/ppapi/proxy/resource_reply_thread_registrar.cc
index d0c697deab7338603c7db9f04f65bfa1279b55b1..274d90264923f6f642ffa65bd7b331f8aeb61826 100644
--- a/ppapi/proxy/resource_reply_thread_registrar.cc
+++ b/ppapi/proxy/resource_reply_thread_registrar.cc
@@ -50,11 +50,6 @@ void ResourceReplyThreadRegistrar::Unregister(PP_Resource resource) {
   map_.erase(resource);
 }
 
-void ResourceReplyThreadRegistrar::HandleOnIOThread(uint32 nested_msg_type) {
-  base::AutoLock auto_lock(lock_);
-  io_thread_message_types_.insert(nested_msg_type);
-}
-
 scoped_refptr<base::MessageLoopProxy>
 ResourceReplyThreadRegistrar::GetTargetThread(
     const ResourceMessageReplyParams& reply_params,
@@ -72,9 +67,6 @@ ResourceReplyThreadRegistrar::GetTargetThread(
     }
   }
 
-  if (io_thread_message_types_.count(nested_msg.type()) != 0)
-    return scoped_refptr<base::MessageLoopProxy>();
-
   return main_thread_;
 }