[Media Router] Allow casting new media to sink with existing route.

chrome/browser/resources/media_router/media_router_data.js

 // 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.
 
 // Any strings used here will already be localized. Values such as
 // CastMode.type or IDs will be defined elsewhere and determined later.
 
 cr.exportPath('media_router');
 
 /**
@@ skipping 32 matching lines @@
 /**
  * This corresponds to the C++ MediaRouterMetrics MediaRouterUserAction.
  * @enum {number}
  */
 media_router.MediaRouterUserAction = {
   CHANGE_MODE: 0,
   START_LOCAL: 1,
   STOP_LOCAL: 2,
   CLOSE: 3,
   STATUS_REMOTE: 4,
+  REPLACE_LOCAL_ROUTE: 5,
 };
 
 /**
  * The possible states of the Media Router dialog. Used to determine which
  * components to show.
  * @enum {string}
  */
 media_router.MediaRouterView = {
   CAST_MODE_LIST: 'cast-mode-list',
   FILTER: 'filter',
@@ skipping 194 matching lines @@
 
   return {
     AUTO_CAST_MODE: AUTO_CAST_MODE,
     CastMode: CastMode,
     Issue: Issue,
     Route: Route,
     Sink: Sink,
     TabInfo: TabInfo,
   };
 });