Revert "Add support for timezone offset and timezone name."

runtime/lib/date.dart

Index: runtime/lib/date.dart
diff --git a/runtime/lib/date.dart b/runtime/lib/date.dart
index 97395aed124284628348d47c4de312c9fddf5805..3e33c3aa2b266269f0aae52157da485fc6d9c756 100644
--- a/runtime/lib/date.dart
+++ b/runtime/lib/date.dart
@@ -130,18 +130,6 @@ class DateImplementation implements Date {
     return new Date.fromEpoch(value, targetTimeZone);
   }
 
-  String get timeZoneName() {
-    if (isUtc()) return "UTC";
-    return _timeZoneName(_equivalentSeconds(_secondsSinceEpoch));
-  }
-
-  Duration get timeZoneOffset() {
-    if (isUtc()) return new Duration(0);
-    int offsetInSeconds =
-        _timeZoneOffsetInSeconds(_equivalentSeconds(_secondsSinceEpoch));
-    return new Duration(seconds: offsetInSeconds);
-  }
-
   int get year() {
     int secondsSinceEpoch = _secondsSinceEpoch;
     // According to V8 some library calls have troubles with negative values.
@@ -413,12 +401,6 @@ class DateImplementation implements Date {
 
   static int _getCurrentMs() native "DateNatives_currentTimeMillis";
 
-  static String _timeZoneName(int secondsSinceEpoch)
-      native "DateNatives_timeZoneName";
-
-  static int _timeZoneOffsetInSeconds(int secondsSinceEpoch)
-      native "DateNatives_timeZoneOffsetInSeconds";
-
   // TODO(floitsch): it would be more efficient if we didn't call the native
   // function for every member, but cached the broken-down date.
   static int _getYear(int secondsSinceEpoch, bool isUtc)