Remove remaining calls to deprecated MessageLoop methods on Mac.

extensions/browser/api/cast_channel/cast_test_util.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef EXTENSIONS_BROWSER_API_CAST_CHANNEL_CAST_TEST_UTIL_H_
 #define EXTENSIONS_BROWSER_API_CAST_CHANNEL_CAST_TEST_UTIL_H_
 
 #include <string>
 #include <utility>
 
 #include "base/macros.h"
-#include "base/message_loop/message_loop.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "extensions/browser/api/cast_channel/cast_socket.h"
 #include "extensions/browser/api/cast_channel/cast_transport.h"
 #include "extensions/common/api/cast_channel/cast_channel.pb.h"
 #include "net/base/ip_endpoint.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace extensions {
 namespace api {
 namespace cast_channel {
 
@@ skipping 86 matching lines @@
 MATCHER_P(EqualsProto, message, "") {
   std::string expected_serialized, actual_serialized;
   message.SerializeToString(&expected_serialized);
   arg.SerializeToString(&actual_serialized);
   return expected_serialized == actual_serialized;
 }
 
 ACTION_TEMPLATE(PostCompletionCallbackTask,
                 HAS_1_TEMPLATE_PARAMS(int, cb_idx),
                 AND_1_VALUE_PARAMS(rv)) {
-  base::MessageLoop::current()->PostTask(
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE, base::Bind(testing::get<cb_idx>(args), rv));
 }
 
 }  // namespace cast_channel
 }  // namespace api
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_CAST_CHANNEL_CAST_TEST_UTIL_H_