Revert "Switch libraries to using new tags."

sdk/lib/core/future_impl.dart

 // Copyright 2012 Google Inc. All Rights Reserved.
 // Dart core library.
 
-part of dart.core;
-
 class _FutureImpl<T> implements Future<T> {
 
   bool _isComplete = false;
 
   /**
    * Value that was provided to this Future by the Completer
    */
   T _value;
 
   /**
@@ skipping 266 matching lines @@
 
   void complete(T value) {
     _futureImpl._setValue(value);
   }
 
   void completeException(Object exception, [Object stackTrace]) {
     _futureImpl._setException(exception, stackTrace);
   }
 }