Added polyfill for var (moved from web_ui)

pkg/csslib/test/testing.dart

Index: pkg/csslib/test/testing.dart
diff --git a/pkg/csslib/test/testing.dart b/pkg/csslib/test/testing.dart
index e7b14bdc494c62ae39753783b5b6a3fbdb27553e..f2e1273b0222d9a73801d98ad674c9efcf73cfa0 100644
--- a/pkg/csslib/test/testing.dart
+++ b/pkg/csslib/test/testing.dart
@@ -27,9 +27,11 @@ StyleSheet parseCss(String cssInput, {List errors, List opts}) =>
  * CSS will allow any property/value pairs regardless of validity; all of our
  * tests (by default) will ensure that the CSS is really valid.
  */
-StyleSheet compileCss(String cssInput, {List errors, List opts}) =>
+StyleSheet compileCss(String cssInput,
+    {List errors, List opts, bool polyfill: false}) =>
   compile(cssInput, errors: errors, options: opts == null ?
-      ['--no-colors', '--checked', '--warnings_as_errors', 'memory'] : opts);
+      ['--no-colors', '--checked', '--warnings_as_errors', 'memory'] : opts,
+      polyfill: polyfill);
 
 /** CSS emitter walks the style sheet tree and emits readable CSS. */
 var _emitCss = new CssPrinter();