Refactor Date.

corelib/src/time_zone.dart

Index: corelib/src/time_zone.dart
diff --git a/corelib/src/time_zone.dart b/corelib/src/time_zone.dart
deleted file mode 100644
index 89f6cc59170b39a1778586838b5b1e5bf14aec59..0000000000000000000000000000000000000000
--- a/corelib/src/time_zone.dart
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// Dart core library.
-
-/**
- * [TimeZone]s represent locations (for example Europe/Paris).
- */
-interface TimeZone default TimeZoneImplementation {
-  const TimeZone.utc();
-  TimeZone.local();
-  bool get isUtc();
-}