Rename Error to RequestError in analysis server API.

pkg/analysis_server/test/integration/integration_tests.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;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:convert';
 import 'dart:io';
@@ skipping 186 matching lines @@
     return server.exitCode.timeout(SHUTDOWN_TIMEOUT, onTimeout: () {
       return server.kill();
     });
   }
 }
 
 final Matcher isResponse = new MatchesJsonObject('response', {
   'id': isString
 }, optionalFields: {
   'result': anything,
-  'error': isError
+  'error': isRequestError
 });
 
 const Matcher isNotification = const MatchesJsonObject('notification', const {
   'event': isString
 }, optionalFields: const {
   'params': isMap
 });
 
 const Matcher isString = const isInstanceOf<String>('String');
 
@@ skipping 611 matching lines @@
    */
   void _recordStdio(String line) {
     double elapsedTime = _time.elapsedTicks / _time.frequency;
     line = "$elapsedTime: $line";
     if (_debuggingStdio) {
       print(line);
     }
     _recordedStdio.add(line);
   }
 }