Use ScopedTaskEnvironment instead of MessageLoop in content unit tests.

content/browser/fileapi/copy_or_move_file_validator_unittest.cc

 // Copyright 2013 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 <stddef.h>
 #include <stdint.h>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "content/public/test/async_file_test_helper.h"
 #include "content/public/test/mock_special_storage_policy.h"
 #include "content/public/test/test_file_system_backend.h"
 #include "content/public/test/test_file_system_context.h"
 #include "storage/browser/blob/shareable_file_reference.h"
 #include "storage/browser/fileapi/copy_or_move_file_validator.h"
 #include "storage/browser/fileapi/external_mount_points.h"
 #include "storage/browser/fileapi/file_system_backend.h"
 #include "storage/browser/fileapi/file_system_context.h"
@@ skipping 146 matching lines @@
 
   base::ScopedTempDir base_;
 
   const GURL origin_;
 
   const storage::FileSystemType src_type_;
   const storage::FileSystemType dest_type_;
   std::string src_fsid_;
   std::string dest_fsid_;
 
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   scoped_refptr<storage::FileSystemContext> file_system_context_;
 
   FileSystemURL copy_src_;
   FileSystemURL copy_dest_;
   FileSystemURL move_src_;
   FileSystemURL move_dest_;
 
   DISALLOW_COPY_AND_ASSIGN(CopyOrMoveFileValidatorTestHelper);
 };
 
@@ skipping 134 matching lines @@
   helper.SetUp();
   std::unique_ptr<CopyOrMoveFileValidatorFactory> factory(
       new TestCopyOrMoveFileValidatorFactory(POST_WRITE_INVALID));
   helper.SetMediaCopyOrMoveFileValidatorFactory(std::move(factory));
 
   helper.CopyTest(base::File::FILE_ERROR_SECURITY);
   helper.MoveTest(base::File::FILE_ERROR_SECURITY);
 }
 
 }  // namespace content