Switch statement cleanups.

pkg/analysis_server/lib/src/analysis_manager.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:convert';
 import 'dart:io';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/channel/channel.dart';
@@ skipping 99 matching lines @@
       }
       throw 'Failed to connect to analysis server at $serverUrl\n  $error';
     };
     try {
       WebSocket socket = await WebSocket.connect(serverUrl).catchError(onError);
       this.channel = new WebSocketClientChannel(socket);
       return this;
     } catch (error) {
       onError(error);
     }
+    return null;
   }
 
   /**
    * Open a connection to a running analysis server
    * and return a future with a manager for that analysis server.
    */
   static Future<AnalysisManager> connect(String serverUrl) {
     return new AnalysisManager()._openConnection(serverUrl);
   }
 
   /**
    * Launch analysis server in a separate process
    * and return a future with a manager for that analysis server.
    */
   static Future<AnalysisManager> start(String serverPath) {
     return new AnalysisManager()._launchServer(serverPath);
   }
 }