Remove more libraries directives from server

pkg/analysis_server/lib/src/services/completion/completion_performance.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 services.completion.manager;
-
 import 'package:analyzer/src/generated/source.dart';
 
 /**
  * Overall performance of a code completion operation.
  */
 class CompletionPerformance {
   final DateTime start = new DateTime.now();
   final Map<String, Duration> _startTimes = new Map<String, Duration>();
   final Stopwatch _stopwatch = new Stopwatch();
   final List<OperationPerformance> operations = <OperationPerformance>[];
@@ skipping 93 matching lines @@
    */
   final String name;
 
   /**
    * The elapse time or `null` if undefined.
    */
   final Duration elapsed;
 
   OperationPerformance(this.name, this.elapsed);
 }