[Media Router] Make per-hostname cast mode selections persist

chrome/browser/resources/media_router/media_router_ui_interface.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.
 
 // API invoked by the browser MediaRouterWebUIMessageHandler to communicate
 // with this UI.
 cr.define('media_router.ui', function() {
   'use strict';
 
   // The media-router-container element.
@@ skipping 92 matching lines @@
    *   sinksAndIdentity - list of sinks to be displayed and user identity.
    *   routes - list of routes that are associated with the sinks.
    *   castModes - list of available cast modes.
    */
   function setInitialData(data) {
     container.deviceMissingUrl = data['deviceMissingUrl'];
     container.castModeList = data['castModes'];
     this.setSinkListAndIdentity(data['sinksAndIdentity']);
     container.routeList = data['routes'];
     container.maybeShowRouteDetailsOnOpen();
+    if (data['initialCastMode'] !== undefined)
+      container.setInitialCastMode(data['initialCastMode']);
     media_router.browserApi.onInitialDataReceived();
   }
 
   /**
    * Sets current issue to |issue|, or clears the current issue if |issue| is
    * null.
    *
    * @param {?media_router.Issue} issue
    */
   function setIssue(issue) {
@@ skipping 292 matching lines @@
     reportRouteCreationOutcome: reportRouteCreationOutcome,
     reportSelectedCastMode: reportSelectedCastMode,
     reportSinkCount: reportSinkCount,
     reportTimeToClickSink: reportTimeToClickSink,
     reportTimeToInitialActionClose: reportTimeToInitialActionClose,
     requestInitialData: requestInitialData,
     requestRoute: requestRoute,
     searchSinksAndCreateRoute: searchSinksAndCreateRoute,
   };
 });