[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_

[ncarter (slow), 2016/05/06 21:50:57]

Ignore this LHS.

+#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);
+// Implementation of the TaskManagerTester for the old task manager.
+class LegacyTaskManagerTester : public browsertest_util::TaskManagerTester {

[afakhry, 2016/05/07 00:16:09]

mmm, what's the benefit of an extra level here? i.e. why did you split it into
LegacyTaskManagerTester and LegacyTaskManagerTesterImpl?

Is it a matter of just hiding the Impl?

[ncarter (slow), 2016/05/07 22:27:10]

It's about hiding the impl and preventing anybody from using the class directly,
while still having a logical home for the factory function. It also results in
fewer lines of code than declaring all the methods in the header.

[afakhry, 2016/05/09 17:46:44]

I honestly think it's an overkill. The object can still be used through
(TaskManagerTester*), and created through the factory method.

+ public:
+  // Create a LegacyTaskManagerTester for the old (deprecated, mac-only) task
+  // manager. If you're writing a test, don't use this directly: see
+  // GetTaskManagerTester() instead.
+  static std::unique_ptr<LegacyTaskManagerTester> Create(
+      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_