Remove remaining calls to deprecated MessageLoop methods.

remoting/host/desktop_process_unittest.cc

Index: remoting/host/desktop_process_unittest.cc
diff --git a/remoting/host/desktop_process_unittest.cc b/remoting/host/desktop_process_unittest.cc
index 15da5e0456d6b023d837ad82e540fb0340c42986..a817c2bc40ffef910da1aa442246ad492d520558 100644
--- a/remoting/host/desktop_process_unittest.cc
+++ b/remoting/host/desktop_process_unittest.cc
@@ -248,8 +248,9 @@ void DesktopProcessTest::DisconnectChannels() {
 }
 
 void DesktopProcessTest::PostDisconnectChannels() {
-  message_loop_.PostTask(FROM_HERE, base::Bind(
-      &DesktopProcessTest::DisconnectChannels, base::Unretained(this)));
+  message_loop_.task_runner()->PostTask(
+      FROM_HERE, base::Bind(&DesktopProcessTest::DisconnectChannels,
+                            base::Unretained(this)));
 }
 
 void DesktopProcessTest::RunDesktopProcess() {