Use ScopedTaskEnvironment instead of MessageLoop in components unit tests.

components/suggestions/image_manager_unittest.cc

 // 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.
 
 #include "components/suggestions/image_manager.h"
 
 #include <memory>
 #include <string>
 
 #include "base/files/file_path.h"
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/image_fetcher/core/image_fetcher.h"
 #include "components/image_fetcher/core/image_fetcher_delegate.h"
 #include "components/leveldb_proto/proto_database.h"
 #include "components/leveldb_proto/testing/fake_db.h"
 #include "components/suggestions/image_encoder.h"
 #include "components/suggestions/proto/suggestions.pb.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/geometry/size.h"
@@ skipping 109 matching lines @@
 
   EntryMap db_model_;
   // Owned by the ImageManager under test.
   FakeDB<ImageData>* fake_db_;
 
   MockImageFetcher* mock_image_fetcher_;
 
   int num_callback_null_called_;
   int num_callback_valid_called_;
 
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
 
   // Under test.
   std::unique_ptr<ImageManager> image_manager_;
 };
 
 TEST_F(ImageManagerTest, InitializeTest) {
   SuggestionsProfile suggestions_profile;
   ChromeSuggestion* suggestion = suggestions_profile.add_suggestions();
   suggestion->set_url(kTestUrl1);
   suggestion->set_thumbnail(kTestImagePath);
@@ skipping 65 matching lines @@
   image_manager_->GetImageForURL(GURL(kTestUrl1),
                                  base::Bind(&ImageManagerTest::OnImageAvailable,
                                             base::Unretained(this), &run_loop));
   run_loop.Run();
 
   EXPECT_EQ(0, num_callback_null_called_);
   EXPECT_EQ(1, num_callback_valid_called_);
 }
 
 }  // namespace suggestions