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

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 2d8d0741f9dd6ba16169181b6ef33dccbfaac771..49c03fa9b4a2d3c57ced3b23140afd10b830b059 100644
--- a/chrome/test/data/webui/media_router/route_details_tests.js
+++ b/chrome/test/data/webui/media_router/route_details_tests.js
@@ -95,10 +95,22 @@ cr.define('route_details', function() {
       });
 
       // Tests for 'start-casting-to-route-click' event firing when the
-      // 'start-casting-to-route-button' button is clicked.
+      // 'start-casting-to-route-button' button is clicked when the current
+      // route is joinable.
       test('start casting to route button click', function(done) {
         details.addEventListener(
             'start-casting-to-route-click', function() { done(); });
+        details.route = fakeRouteTwo;
+        MockInteractions.tap(details.$['start-casting-to-route-button']);
+      });
+
+      // Tests for 'cast-new-media-click' event firing when the
+      // 'start-casting-to-route-button' button is clicked when the current
+      // route is not joinable.
+      test('start casting button click starts new media', function(done) {
+        details.addEventListener(
+            'cast-new-media-click', function() { done(); });
+        details.route = fakeRouteOne;
         MockInteractions.tap(details.$['start-casting-to-route-button']);
       });
 
@@ -125,7 +137,7 @@ cr.define('route_details', function() {
         checkSpanText(loadTimeData.getStringF('castingActivityStatus',
             fakeRouteOne.description), 'route-information');
         checkDefaultViewIsShown();
-        checkStartCastButtonIsNotShown();
+        checkStartCastButtonIsShown();
 
         // Set |route| to a different route.
         details.route = fakeRouteTwo;