Add media router common classes and unittests.

chrome/browser/media/router/media_sink.h

+// Copyright 2015 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_SINK_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_MEDIA_SINK_H_
+
+#include <string>
+
+#include "chrome/browser/media/router/media_route_id.h"
+
+namespace media_router {
+
+typedef std::string MediaSinkId;
+
+// Represents a sink to which media can be routed.
+class MediaSink {
+ public:
+  enum Status {

[mark a. foltz, 2015/03/02 21:40:10]

It would be a good idea to document the state transitions for this object.

[Kevin M, 2015/03/03 21:53:19]

Done.

+    // The sink is currently not associated with any routes.
+    IDLE,
+    // The sink is currently associated with a route.
+    ACTIVE,
+    // The sink has a pending route request.
+    REQUEST_PENDING

[mark a. foltz, 2015/03/02 21:40:10]

Can a sink ever have a request pending while it is also active?

This feels like it could be an independent boolean attribute (separate from
active/idle status).

[Kevin M, 2015/03/03 21:53:19]

I talked this over with imcheng and he's thinking that Status might be worth
removing entirely, as it hasn't proved to be useful so far.

Removed it.

+  };
+
+  // |sink_id|: Unique identifier for the MediaSink.
+  // |name|: Descriptive name of the MediaSink.

[mark a. foltz, 2015/03/02 21:40:09]

Does this represent a localized string?  If so, is std::string the right type
for conveying it?  (I haven't dealt with UI strings personally - miu@ would be
able to tell you right away.)

[Kevin M, 2015/03/03 21:53:20]

The string data we get from Mojo is a UTF-8 encoded std::string, so the
character encodings should remain intact if we pass it around as a std::string.

[mark a. foltz, 2015/03/04 06:22:58]

We should touch base about rendering requirements and again see if we should
pass locale information here.

[Kevin M, 2015/03/04 23:33:32]

Sure, I'll talk to you in person, maybe including apacible@?

+  // |status|: Current status of the MediaSink.
+  MediaSink(const MediaSinkId& sink_id,
+            const std::string& name,
+            Status status);
+  ~MediaSink();
+
+  const MediaSinkId& sink_id() const { return sink_id_; }
+  const std::string& name() const { return name_; }
+  Status status() const { return status_; }
+  std::string StatusAsString() const;
+
+  bool operator==(const MediaSink& other) const;
+  bool operator!=(const MediaSink& other) const;
+
+ private:
+  MediaSinkId sink_id_;
+  std::string name_;
+  Status status_;
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_MEDIA_SINK_H_