Move the wire protocol support into the public API

pkg/analysis_server/test/integration/analysis/overrides_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.integration.analysis.overrides;
 
-import 'package:analysis_server/src/protocol.dart';
+import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 import 'package:unittest/unittest.dart';
 
 import '../../utils.dart';
 import '../integration_tests.dart';
 
 main() {
   initializeTestEnvironment();
   defineReflectiveTests(Test);
 }
@@ skipping 95 matching lines @@
       checkOverrides('method1', false, ['Interface1', 'Interface2']);
       checkOverrides('method2', true, ['Interface1']);
       checkOverrides('method3', false, ['Interface1']);
       checkOverrides('method4', true, ['Interface2']);
       checkOverrides('method5', false, ['Interface2']);
       checkOverrides('method6', true, []);
       checkOverrides('method7', false, []);
     });
   }
 }