[Part 4 of 6] Split LegacyTaskManagerTester into its own file.

chrome/browser/task_manager/legacy_task_manager_tester.h

 // 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.
 
-#ifndef MEDIA_MOJO_SERVICES_MOJO_MEDIA_APPLICATION_FACTORY_H_
-#define MEDIA_MOJO_SERVICES_MOJO_MEDIA_APPLICATION_FACTORY_H_
+#ifndef CHROME_BROWSER_TASK_MANAGER_LEGACY_TASK_MANAGER_TESTER_H_
+#define CHROME_BROWSER_TASK_MANAGER_LEGACY_TASK_MANAGER_TESTER_H_
 
 #include <memory>
 
 #include "base/callback_forward.h"
-#include "services/shell/public/cpp/shell_client.h"
+#include "chrome/browser/task_manager/task_manager_browsertest_util.h"
 
-namespace media {
+namespace task_manager {
 
-// Creates a MojoMediaApplication instance using the default MojoMediaClient.
-std::unique_ptr<shell::ShellClient> CreateMojoMediaApplication(
-    const base::Closure& quit_closure);
+// Create a LegacyTaskManagerTester for the old (deprecated, mac-only) task
+// manager. If you're writing a test, don't use this directly since it won't
+// work on other platforms. Use TaskManagerTester::Create() instead.
+std::unique_ptr<browsertest_util::TaskManagerTester>
+CreateLegacyTaskManagerTester(const base::Closure& callback);
 
-}  // namespace media
+}  // namespace task_manager
 
-#endif  // MEDIA_MOJO_SERVICES_MOJO_MEDIA_APPLICATION_FACTORY_H_
+#endif  // CHROME_BROWSER_TASK_MANAGER_LEGACY_TASK_MANAGER_TESTER_H_