More strong mode changes in analysis_server

pkg/analysis_server/test/protocol_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.protocol;
 
 import 'dart:convert';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/constants.dart';
@@ skipping 248 matching lines @@
     expect(response.error, isNotNull);
     RequestError error = response.error;
     expect(error.code, equals(RequestErrorCode.INVALID_REQUEST));
     expect(error.message, equals('Invalid request'));
   }
 
   void test_fromJson_withResult() {
     Response original = new Response('myId', result: {'foo': 'bar'});
     Response response = new Response.fromJson(original.toJson());
     expect(response.id, equals('myId'));
-    Map<String, Object> result = response.toJson()['result'];
+    Map<String, Object> result =
+        response.toJson()['result'] as Map<String, Object>;
     expect(result.length, equals(1));
     expect(result['foo'], equals('bar'));
   }
 }