Remove calls to deprecated MessageLoop methods in components/previews/.

components/previews/previews_ui_service_unittest.cc

 // Copyright 2016 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.
 
 #include "components/previews/previews_ui_service.h"
 
 #include <memory>
 
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "components/previews/previews_io_data.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace previews {
 
 namespace {
 
 class TestPreviewsUIService : public PreviewsUIService {
  public:
@@ skipping 45 matching lines @@
   std::unique_ptr<TestPreviewsUIService> ui_service_;
 };
 
 }  // namespace
 
 TEST_F(PreviewsUIServiceTest, TestInitialization) {
   set_io_data(base::WrapUnique(
       new PreviewsIOData(loop_.task_runner(), loop_.task_runner())));
   set_ui_service(base::WrapUnique(
       new TestPreviewsUIService(io_data(), loop_.task_runner())));
-  loop_.RunUntilIdle();
+  base::RunLoop().RunUntilIdle();
   // After the outstanding posted tasks have run, SetIOData should have been
   // called for |ui_service_|.
   EXPECT_TRUE(ui_service()->io_data_set());
 }
 
 }  // namespace previews