Remove uses of unittest in the HTML tests where possible.

pkg/dev_compiler/test/codegen/lib/html/navigator_test.dart

Index: pkg/dev_compiler/test/codegen/lib/html/navigator_test.dart
diff --git a/pkg/dev_compiler/test/codegen/lib/html/navigator_test.dart b/pkg/dev_compiler/test/codegen/lib/html/navigator_test.dart
index 2bc5cc8912749db3e0f117b72924d5d75c71ad43..c0f2627668c46aa762da382c5252336b9737c2d4 100644
--- a/pkg/dev_compiler/test/codegen/lib/html/navigator_test.dart
+++ b/pkg/dev_compiler/test/codegen/lib/html/navigator_test.dart
@@ -1,12 +1,7 @@
-library NavigatorTest;
-import 'package:unittest/unittest.dart';
-import 'package:unittest/html_config.dart';
 import 'dart:html';
 
-main() {
-  useHtmlConfiguration();
+import 'package:expect/expect.dart';
 
-  test('language never returns null', () {
-      expect(window.navigator.language, isNotNull);
-    });
+main() {
+  Expect.isNotNull(window.navigator.language);

[Jacob, 2016/10/14 16:44:38]

nit: why delete the test block here? I know the test name is somewhat obvious
from the expect but still deems reasonable to make summaries of errors look
nice.

 }