Clean up package imports and library names

pkg/analyzer/lib/src/cancelable_future.dart

 // Copyright (c) 2014, 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.
 
-library cancelable_future;
+library analyzer.src.cancelable_future;
 
 import 'dart:async';
 
 /**
  * Type of callback called when the future returned by a CancelableCompleter
  * is canceled.
  */
 typedef void CancelHandler();
 
 /**
@@ skipping 275 matching lines @@
   Future then(onValue(value), {Function onError}) =>
       _future.then(onValue, onError: onError);
 
   @override
   Future timeout(Duration timeLimit, {onTimeout()}) =>
       _future.timeout(timeLimit, onTimeout: onTimeout);
 
   @override
   Future<T> whenComplete(action()) => _future.whenComplete(action);
 }