Add media router common classes and unittests.

chrome/browser/media/router/media_sink.cc

+// 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.
+
+#include "chrome/browser/media/router/media_sink.h"
+
+#include "base/logging.h"
+
+namespace media_router {
+
+MediaSink::MediaSink(const MediaSinkId& sink_id,
+                     const std::string& name,
+                     Status status)
+    : sink_id_(sink_id), name_(name), status_(status) {
+}
+
+MediaSink::~MediaSink() {
+}
+
+std::string MediaSink::StatusAsString() const {
+  switch (status_) {
+    case MediaSink::IDLE:
+      return "IDLE";
+    case MediaSink::ACTIVE:
+      return "ACTIVE";
+    case MediaSink::REQUEST_PENDING:
+      return "REQUEST_PENDING";
+    default:
+      NOTREACHED();
+      return "";
+  }
+}
+
+bool MediaSink::operator==(const MediaSink& other) const {
+  return sink_id_ == other.sink_id_ &&

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

Is comparison by sink_id sufficient?

Since this has mutable state we don't want multiple objects representing the
same MediaSink.

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

Done.

+         name_ == other.name_ &&
+         status_ == other.status_;
+}
+
+bool MediaSink::operator!=(const MediaSink& other) const {
+  return !(*this == other);

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

Or more simply sink_id_ != other.sink_id_

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

Done.

+}
+
+}  // namespace media_router