anchor.diff:  
     @override
     Future<int> run() async {
  -    if (argResults['mojo-path'] == null) {
  -      _logging.severe('Must specify --mojo-path to mojo_run');
  +    if (argResults['mojo-path'] == null && !argResults['android']) {
  +      _logging.severe('Must specify --mojo-path for Linux.');
  +      return 1;
  +    }
  +
  +    if (argResults['devtools-path'] == null && argResults['android']) {
  +      _logging.severe('Must specify --devtools-path for Android.');
         return 1;
       }
       if (argResults['mojo-debug'] && argResults['mojo-release']) {
  
positive.code: 
      args.addAll(argResults.rest);
      if (argResults['android']) {
        return _runAndroid(mojoPath, mojoConfig, appPath, args);
      } else {
        return _runLinux(mojoPath, mojoConfig, appPath, args);
      }
  
negative.code:     return file.absolute.path;
    }
  
    Future<int> _runAndroid(String devtoolsPath, _MojoConfig mojoConfig, String appPath, List<String> additionalArgs) {
      String skyViewerUrl = ArtifactStore.googleStorageUrl('viewer', 'android-arm');
      String command = _makePathAbsolute(devtoolsPath);
      String appName = path.basename(appPath);
      String appDir = path.dirname(appPath);
      String buildFlag = mojoConfig == _MojoConfig.Debug ? '--debug' : '--release';
  