Ignore two unused element warnings in pkg/analysis_server.

pkg/analysis_server/lib/src/analysis_server.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.
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:core';
 import 'dart:io' as io;
 import 'dart:math' show max;
 
@@ skipping 1329 matching lines @@
     return new server.AnalysisNavigationParams(
         path, collector.regions, collector.targets, collector.files);
   }
 
   List<Occurrences> _computeOccurrences(CompilationUnit unit) {
     OccurrencesCollectorImpl collector = new OccurrencesCollectorImpl();
     addDartOccurrences(collector, unit);
     return collector.allOccurrences;
   }
 
+  // ignore: unused_element
   server.AnalysisOutlineParams _computeOutlineParams(
       String path, CompilationUnit unit, LineInfo lineInfo) {
     // compute FileKind
     SourceKind sourceKind = unit.directives.any((d) => d is PartOfDirective)
         ? SourceKind.PART
         : SourceKind.LIBRARY;
     server.FileKind fileKind = server.FileKind.LIBRARY;
     if (sourceKind == SourceKind.LIBRARY) {
       fileKind = server.FileKind.LIBRARY;
     } else if (sourceKind == SourceKind.PART) {
@@ skipping 143 matching lines @@
   /**
    * The [PerformanceTag] for time spent in server request handlers.
    */
   static PerformanceTag serverRequests = server.createChild('requests');
 
   /**
    * The [PerformanceTag] for time spent in split store microtasks.
    */
   static PerformanceTag splitStore = new PerformanceTag('splitStore');
 }