Make server use the common protocol classes

pkg/analysis_server/test/services/completion/dart/completion_contributor_util.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 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/ide_options.dart';
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/completion_core.dart';
 import 'package:analysis_server/src/services/completion/completion_performance.dart';
 import 'package:analysis_server/src/services/completion/dart/completion_manager.dart'
     show DartCompletionRequestImpl, ReplacementRange;
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/source/package_map_resolver.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
 import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 
 import '../../../abstract_context.dart';
 import '../../correction/flutter_util.dart';
 
 int suggestionComparator(CompletionSuggestion s1, CompletionSuggestion s2) {
   String c1 = s1.completion.toLowerCase();
   String c2 = s2.completion.toLowerCase();
   return c1.compareTo(c2);
 }
@@ skipping 554 matching lines @@
   void resolveSource(String path, String content) {
     addSource(path, content);
   }
 
   @override
   void setUp() {
     super.setUp();
     contributor = createContributor();
   }
 }