Move the wire protocol support into the public API

pkg/analysis_server/lib/src/domain_execution.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 domain.execution;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:core' hide Resource;
 
+import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/constants.dart';
-import 'package:analysis_server/src/protocol.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 
 /**
  * Instances of the class [ExecutionDomainHandler] implement a [RequestHandler]
  * that handles requests in the `execution` domain.
  */
 class ExecutionDomainHandler implements RequestHandler {
   /**
@@ skipping 211 matching lines @@
     if (_isInAnalysisRoot(filePath)) {
       server.sendNotification(
           new ExecutionLaunchDataParams(filePath, kind: kind).toNotification());
     }
   }
 
   static List<String> _getFullNames(List<Source> sources) {
     return sources.map((Source source) => source.fullName).toList();
   }
 }