More strong mode changes to analysis_server

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 57 matching lines @@
       return _listenForPort(process);
     } catch (error) {
       exitCode = 1;
       throw 'Failed to launch analysis server: $error';
     }
   }
 
   /**
    * Listen for a port from the given analysis server process.
    */
-  Future<AnalysisManager> _listenForPort(Process process) {
+  Future<AnalysisManager> _listenForPort(Process process) async {
     this.process = process;
 
     // Echo stdout and stderr
     Stream out = process.stdout.transform(UTF8.decoder).asBroadcastStream();
     out.listen((line) => print(line));
     process.stderr.pipe(stderr);
 
     // Listen for port from server
     const String pattern = 'Listening on port ';
-    return out
-        .firstWhere((String line) => line.startsWith(pattern))
-        .timeout(new Duration(seconds: 10))
-        .catchError((error) {
+    try {
+      String line = await out
+          .firstWhere((String line) => line.startsWith(pattern))
+          .timeout(new Duration(seconds: 10));
+      String port = line.substring(pattern.length).trim();
+      String url = 'ws://${InternetAddress.LOOPBACK_IP_V4.address}:$port/';
+      return _openConnection(url);
+    } catch (error) {
       exitCode = 1;
       process.kill();
       throw 'Expected port from analysis server';
-    }).then((String line) {
-      String port = line.substring(pattern.length).trim();
-      String url = 'ws://${InternetAddress.LOOPBACK_IP_V4.address}:$port/';
-      return _openConnection(url);
-    });
+    }
   }
 
   /**
    * Open a connection to the analysis server using the given URL.
    */
   Future<AnalysisManager> _openConnection(String serverUrl) {
     Function onError = (error) {
       exitCode = 1;
       if (process != null) {
         process.kill();
@@ skipping 22 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);
   }
 }