removeFromOpenedFiles (pathname) {
    const { _openedFiles, browserWindow } = this
    const index = _openedFiles.findIndex(p => p === pathname)
    if (index !== -1) {
      _openedFiles.splice(index, 1)
    }
    ipcMain.emit('watcher-unwatch-file', browserWindow, pathname)
  }
Remove a path from the opened file list and stop watching the path.

@param {string} pathname The full path.