anchor.diff:  
       args.addAll(argResults.rest);
       if (argResults['android']) {
  -      return _runAndroid(argResults['devtools-path'], mojoConfig, appPath, args);
  +      return _runAndroid(mojoPath, mojoConfig, appPath, args);
       } else {
         return _runLinux(mojoPath, mojoConfig, appPath, args);
       }
  
positive.code:     argParser.addFlag('mojo-release', negatable: false, help: 'Use Release build of mojo (default)');
  
      argParser.addOption('app', defaultsTo: 'app.flx');
      argParser.addOption('mojo-path', help: 'Path to directory containing mojo_shell and services. This is required for a Linux build.');
      argParser.addOption('devtools-path', help: 'Path to the mojo_run script in mojo devtools. This is required for an Android build.');
    }
  
    // TODO(abarth): Why not use path.absolute?
  
negative.code: 
    @override
    Future<int> run() async {
      if (argResults['mojo-path'] == null) {
        _logging.severe('Must specify --mojo-path.');
        return 1;
      }
  
      if (argResults['mojo-debug'] && argResults['mojo-release']) {
        _logging.severe('Cannot specify both --mojo-debug and --mojo-release');
        return 1;
  