[ServiceWorker] Update formatting for tests.

LayoutTests/http/tests/serviceworker/resources/cache-add-worker.js

Index: LayoutTests/http/tests/serviceworker/resources/cache-add-worker.js
diff --git a/LayoutTests/http/tests/serviceworker/resources/cache-add-worker.js b/LayoutTests/http/tests/serviceworker/resources/cache-add-worker.js
index 231fdc4dcfd1f9a3bcac93bb05f4868f5b156988..71b4aa382a9384034578c9fc1a8bfc9e6fbda5e2 100644
--- a/LayoutTests/http/tests/serviceworker/resources/cache-add-worker.js
+++ b/LayoutTests/http/tests/serviceworker/resources/cache-add-worker.js
@@ -102,7 +102,8 @@ cache_test(function(cache) {
     return cache.addAll(urls)
       .then(function(result) {
           assert_equals(result, undefined,
-                        'Cache.addAll should resolve with undefined on success.');
+                        'Cache.addAll should resolve with undefined on ' +
+                        'success.');
         });
   }, 'Cache.addAll with string URL arguments');