Generate constants in server as we do in plugin

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.
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:core';
 
 import 'package:analysis_server/protocol/protocol.dart';
+import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/analysis_server.dart';
-import 'package:analysis_server/src/constants.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/dart/analysis/driver.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 39 matching lines @@
   Response deleteContext(Request request) {
     String contextId = new ExecutionDeleteContextParams.fromRequest(request).id;
     contextMap.remove(contextId);
     return new ExecutionDeleteContextResult().toResponse(request.id);
   }
 
   @override
   Response handleRequest(Request request) {
     try {
       String requestName = request.method;
-      if (requestName == EXECUTION_CREATE_CONTEXT) {
+      if (requestName == EXECUTION_REQUEST_CREATE_CONTEXT) {
         return createContext(request);
-      } else if (requestName == EXECUTION_DELETE_CONTEXT) {
+      } else if (requestName == EXECUTION_REQUEST_DELETE_CONTEXT) {
         return deleteContext(request);
-      } else if (requestName == EXECUTION_MAP_URI) {
+      } else if (requestName == EXECUTION_REQUEST_MAP_URI) {
         return mapUri(request);
-      } else if (requestName == EXECUTION_SET_SUBSCRIPTIONS) {
+      } else if (requestName == EXECUTION_REQUEST_SET_SUBSCRIPTIONS) {
         return setSubscriptions(request);
       }
     } on RequestFailure catch (exception) {
       return exception.response;
     }
     return null;
   }
 
   /**
    * Implement the 'execution.mapUri' request.
@@ skipping 49 matching lines @@
   }
 
   /**
    * Implement the 'execution.setSubscriptions' request.
    */
   Response setSubscriptions(Request request) {
     // Under the analysis driver, setSubscriptions() becomes a no-op.
     return new ExecutionSetSubscriptionsResult().toResponse(request.id);
   }
 }