Add media router common classes and unittests.

chrome/browser/media/router/media_controller_impl.h

+// 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.
+
+#ifndef CHROME_BROWSER_MEDIA_ROUTER_MEDIA_CONTROLLER_IMPL_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_MEDIA_CONTROLLER_IMPL_H_
+
+#include "chrome/browser/media/router/media_controller.h"
+
+namespace media_router {
+
+class MediaControllerImpl : public MediaController {
+ public:
+  explicit MediaControllerImpl(const MediaRouteId& media_route_id);
+  ~MediaControllerImpl() override;
+
+  // MediaController implementation.
+  void Pause() override;
+  void Resume() override;
+  void Play() override;
+  void Stop() override;
+  void Next() override;
+  void Previous() override;
+  void SeekRelative(double seek_seconds) override;
+  void SeekAbsolute(double seek_seconds) override;
+  void VolumeUp() override;
+  void VolumeDown() override;
+  void Mute() override;
+  void Unmute() override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MediaControllerImpl);
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_MEDIA_CONTROLLER_IMPL_H_