Remove calls to deprecated MessageLoop methods from message_loop_unittest.cc.

This CL removes calls to MessageLoop::Post(Delayed)Task from
message_loop_unittest.cc

BUG=616447

Review-Url: https://codereview.chromium.org/2342903002
Cr-Commit-Position: refs/heads/master@{#418925}

base/message_loop/message_loop_unittest.cc

@@ -106,10 +106,11 @@ void RunTest_AbortDontRunMoreTasks(bool delayed) {
   java_thread->Start();
 
   if (delayed) {
-    java_thread->message_loop()->PostDelayedTask(
+    java_thread->message_loop()->task_runner()->PostDelayedTask(
         FROM_HERE, Bind(&AbortMessagePump), TimeDelta::FromMilliseconds(10));
   } else {
-    java_thread->message_loop()->PostTask(FROM_HERE, Bind(&AbortMessagePump));
+    java_thread->message_loop()->task_runner()->PostTask(
+        FROM_HERE, Bind(&AbortMessagePump));
   }
 
   // Wait to ensure we catch the correct exception (and don't crash)