content/child: Remove use of MessageLoopProxy and deprecated MessageLoop APIs

ppapi/nacl_irt/ppapi_dispatcher.cc

Index: ppapi/nacl_irt/ppapi_dispatcher.cc
diff --git a/ppapi/nacl_irt/ppapi_dispatcher.cc b/ppapi/nacl_irt/ppapi_dispatcher.cc
index 343c71c2655f9c9ab01fe6d4bca941ab42d5541b..e6d0283b49bafd8a193580605b32f51a2bd14855 100644
--- a/ppapi/nacl_irt/ppapi_dispatcher.cc
+++ b/ppapi/nacl_irt/ppapi_dispatcher.cc
@@ -65,7 +65,7 @@ PpapiDispatcher::PpapiDispatcher(scoped_refptr<base::MessageLoopProxy> io_loop,
   // ensures that the filters won't miss any messages received by
   // the channel.
   channel_ =
-      IPC::SyncChannel::Create(this, GetIPCMessageLoop(), GetShutdownEvent());
+      IPC::SyncChannel::Create(this, GetIPCTaskRunner(), GetShutdownEvent());
   scoped_refptr<ppapi::proxy::PluginMessageFilter> plugin_filter(
       new ppapi::proxy::PluginMessageFilter(
           NULL, globals->resource_reply_thread_registrar()));
@@ -77,7 +77,7 @@ PpapiDispatcher::PpapiDispatcher(scoped_refptr<base::MessageLoopProxy> io_loop,
   channel_->Init(channel_handle, IPC::Channel::MODE_SERVER, true);
 }
 
-base::MessageLoopProxy* PpapiDispatcher::GetIPCMessageLoop() {
+base::SingleThreadTaskRunner* PpapiDispatcher::GetIPCTaskRunner() {
   return message_loop_.get();
 }