Quote all arguments when printing a Command

tools/testing/dart/test_progress.dart

 // Copyright (c) 2012, 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_progress;
 
 import "dart:io";
 import "dart:io" as io;
 import "http_server.dart" as http_server;
 import "status_file_parser.dart";
@@ skipping 192 matching lines @@
     if (test is BrowserTestCase) {
       // Additional command for rerunning the steps locally after the fact.
       var command =
         test.configuration["_servers_"].httpServerCommandline();
       output.add('To retest, run:  $command');
     }
     for (Command c in test.commands) {
       output.add('');
       String message = (c == test.commands.last
           ? "Command line" : "Compilation command");
-      output.add('$message: ${c.commandLine}');
+      output.add('$message: $c');
     }
     return output;
   }
 
   void _printFailureSummary() {
     for (String line in _failureSummary) {
       print(line);
     }
     print('');
   }
@@ skipping 267 matching lines @@
       print('');
       print('$config:');
       statuses.sort((a, b) => a.compareTo(b));
       for (String status in statuses) {
         print('  $status');
       }
     });
     _printStatus();
   }
 }