Opens stock TensorBoard web assets collection.

  Returns:
    Returns function that returns a newly opened file handle to zip file
    containing static assets for stock TensorBoard, or None if webfiles.zip
    could not be found. The value the callback returns must be closed. The
    paths inside the zip file are considered absolute paths on the web server.

def get_default_assets_zip_provider():
  """Opens stock TensorBoard web assets collection.

  Returns:
    Returns function that returns a newly opened file handle to zip file
    containing static assets for stock TensorBoard, or None if webfiles.zip
    could not be found. The value the callback returns must be closed. The
    paths inside the zip file are considered absolute paths on the web server.
  """
  path = os.path.join(os.path.dirname(inspect.getfile(sys._getframe(1))),
                      'webfiles.zip')
  if not os.path.exists(path):
    logger.warning('webfiles.zip static assets not found: %s', path)
    return None
  return lambda: open(path, 'rb')