Add all dart:html tests from the sdk to test/codegen.

test/codegen/lib/html/cache_test.dart

+library CacheTest;
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_individual_config.dart';
+import 'dart:html';
+
+main() {
+  useHtmlIndividualConfiguration();
+
+  group('supported', () {
+    test('supported', () {
+      expect(ApplicationCache.supported, true);
+    });
+  });
+
+  group('ApplicationCache', () {
+    test('ApplicationCache', () {
+      var expectation = ApplicationCache.supported ? returnsNormally : throws;
+      expect(() {
+        ApplicationCache appCache = window.applicationCache;
+        expect(cacheStatusToString(appCache.status), "UNCACHED");
+      }, expectation);
+
+    });
+  });
+
+}
+
+String cacheStatusToString(int status) {
+  switch (status) {
+    case ApplicationCache.UNCACHED: // UNCACHED == 0
+      return 'UNCACHED';
+    case ApplicationCache.IDLE: // IDLE == 1
+      return 'IDLE';
+    case ApplicationCache.CHECKING: // CHECKING == 2
+      return 'CHECKING';
+    case ApplicationCache.DOWNLOADING: // DOWNLOADING == 3
+      return 'DOWNLOADING';
+    case ApplicationCache.UPDATEREADY:  // UPDATEREADY == 4
+      return 'UPDATEREADY';
+    case ApplicationCache.OBSOLETE: // OBSOLETE == 5
+      return 'OBSOLETE';
+    default:
+      return 'UNKNOWN CACHE STATUS';
+  };
+}