[Media Router WebUI] Move replace route responsibility to extension

chrome/test/data/webui/media_router/route_details_tests.js

Index: chrome/test/data/webui/media_router/route_details_tests.js
diff --git a/chrome/test/data/webui/media_router/route_details_tests.js b/chrome/test/data/webui/media_router/route_details_tests.js
index c4cd0b8e1d83985bafcd9d6b943b7f3eafe8568e..dcab054364afd556eb40b7317709307441ca9cc8 100644
--- a/chrome/test/data/webui/media_router/route_details_tests.js
+++ b/chrome/test/data/webui/media_router/route_details_tests.js
@@ -157,7 +157,7 @@ cr.define('route_details', function() {
       // route is not joinable.
       test('start casting button click replaces route', function(done) {
         details.addEventListener(
-            'replace-route-click', function() { done(); });
+            'change-route-source-click', function() { done(); });
         details.route = fakeRouteOne;
         details.availableCastModes = 1;
         MockInteractions.tap(details.$['start-casting-to-route-button']);