Revert "Converting dart:html to use DateTime rather than Date."

tests/html/fileapi_test.dart

Index: tests/html/fileapi_test.dart
diff --git a/tests/html/fileapi_test.dart b/tests/html/fileapi_test.dart
index 079197fc88204d4df20240bd87015c49d1017098..a2d23d581d6839f882548f71c5c32978b70c44a5 100644
--- a/tests/html/fileapi_test.dart
+++ b/tests/html/fileapi_test.dart
@@ -92,12 +92,6 @@ main() {
             successCallback: expectAsync1((FileEntry e) {
               expect(e.name, equals('file4'));
               expect(e.isFile, isTrue);
-
-              e.getMetadata(expectAsync1((Metadata metadata) {
-                var changeTime = metadata.modificationTime;
-                expect(new DateTime.now().difference(changeTime).inSeconds,
-                  lessThan(60));
-              }));
             }),
             errorCallback: (e) {
               fail('Got file error: ${e.code}');