Start making server strong mode clean

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 42 matching lines @@
       if (result != null && result != 0) {
         exitCode = result;
       }
       return true;
     });
   }
 
   /**
    * Launch an analysis server and open a connection to that server.
    */
-  Future<AnalysisManager> _launchServer(String pathToServer) {
-    // TODO dynamically allocate port and/or allow client to specify port
-    List<String> serverArgs = [pathToServer, '--port', PORT.toString()];
-    return Process.start(Platform.executable, serverArgs).catchError((error) {
+  Future<AnalysisManager> _launchServer(String pathToServer) async {
+    try {
+      // TODO dynamically allocate port and/or allow client to specify port
+      List<String> serverArgs = [pathToServer, '--port', PORT.toString()];
+      Process process = await Process.start(Platform.executable, serverArgs);
+      return _listenForPort(process);
+    } catch (error) {
       exitCode = 1;
       throw 'Failed to launch analysis server: $error';
-    }).then(_listenForPort);
+    }
   }
 
   /**
    * Listen for a port from the given analysis server process.
    */
   Future<AnalysisManager> _listenForPort(Process process) {
     this.process = process;
 
     // Echo stdout and stderr
     Stream out = process.stdout.transform(UTF8.decoder).asBroadcastStream();
@@ skipping 49 matching lines @@
   }
 
   /**
    * 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);
   }
 }