Move the wire protocol support into the public API

pkg/analysis_server/test/services/refactoring/extract_method_test.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 test.services.refactoring.extract_method;
 
 import 'dart:async';
 
-import 'package:analysis_server/src/protocol.dart';
+import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/refactoring/extract_method.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 import 'package:unittest/unittest.dart';
 
 import '../../utils.dart';
 import 'abstract_refactoring.dart';
 
 main() {
@@ skipping 2780 matching lines @@
    * Returns a deep copy of [refactoring] parameters.
    * There was a bug masked by updating parameter instances shared between the
    * refactoring and the test.
    */
   List<RefactoringMethodParameter> _getParametersCopy() {
     return refactoring.parameters.map((p) {
       return new RefactoringMethodParameter(p.kind, p.type, p.name, id: p.id);
     }).toList();
   }
 }