[Media Router WebUI] Move replace route responsibility to extension

chrome/browser/resources/media_router/media_router.js

Index: chrome/browser/resources/media_router/media_router.js
diff --git a/chrome/browser/resources/media_router/media_router.js b/chrome/browser/resources/media_router/media_router.js
index afcee95142e1d9b1bd67000354382b054431297b..b9720a445447ed589901ec8f131dd010871f659a 100644
--- a/chrome/browser/resources/media_router/media_router.js
+++ b/chrome/browser/resources/media_router/media_router.js
@@ -35,6 +35,8 @@ cr.define('media_router', function() {
                                onAcknowledgeFirstRunFlow);
     container.addEventListener('back-click', onNavigateToSinkList);
     container.addEventListener('cast-mode-selected', onCastModeSelected);
+    container.addEventListener('change-route-source-click',
+                               onChangeRouteSourceClick);
     container.addEventListener('close-dialog', onCloseDialog);
     container.addEventListener('close-route', onCloseRoute);
     container.addEventListener('create-route', onCreateRoute);
@@ -97,6 +99,22 @@ cr.define('media_router', function() {
   }
 
   /**
+   * Reports the route for which the users wants to replace the source and the
+   * cast mode that should be used for the new source.
+   *
+   * @param {!Event} event The event object.
+   * Parameters in |event|.detail:
+   *   route - route to modify.
+   *   selectedCastMode - type of cast mode selected by the user.
+   */
+  function onChangeRouteSourceClick(event) {
+    /** @type {{route: !media_router.Route, selectedCastMode: number}} */
+    var detail = event.detail;
+    media_router.browserApi.changeRouteSource(
+        detail.route, detail.selectedCastMode);
+  }
+
+  /**
    * Updates the preference that the user has seen the first run flow.
    * Called when the user clicks on the acknowledgement button on the first run
    * flow.