code: function cleanWww (projectRoot, locations) {
      var targetDir = path.relative(projectRoot, locations.www);
      events.emit('verbose', 'Cleaning ' + targetDir);
  
      // No source paths are specified, so mergeAndUpdateDir() will clear the target directory.
      FileUpdater.mergeAndUpdateDir(
          [], targetDir, { rootDir: projectRoot, all: true }, logFileOp);
  }
docs: Cleans all files from the platform 'www' directory.