Add media router common classes and unittests.

chrome/browser/media/router/media_route.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_route.h"
+
+#include "base/logging.h"
+#include "chrome/browser/media/router/media_source.h"
+
+namespace media_router {
+
+MediaRoute::MediaRoute(const MediaRouteId& media_route_id,
+                       const MediaSource& media_source,
+                       const MediaSink& media_sink,
+                       const std::string& description,
+                       bool is_local)
+    : media_route_id_(media_route_id),
+      media_source_(media_source),
+      media_sink_(media_sink),
+      description_(description),
+      is_local_(is_local),
+      state_(MEDIA_ROUTE_STATE_NEW) {
+}
+
+MediaRoute::~MediaRoute() {
+}
+
+bool MediaRoute::Equals(const MediaRoute& other) const {

[mark a. foltz, 2015/03/10 20:59:37]

Why Equals() instead of implementing operator==?

+  return media_route_id_ == other.media_route_id_;
+}
+
+}  // namespace media_router