function addGalleryChangedListener() {
  chrome.mediaGalleries.onGalleryChanged.addListener(
      onGalleryChangedCallback);
  chrome.test.sendMessage('add_gallery_changed_listener_ok');
}
// Helpers to add and remove event listeners.
Helpers to add and remove event listeners.
Helpers to add and remove event listeners .
function addGalleryChangedListener() {
  chrome.mediaGalleries.onGalleryChanged.addListener(
      onGalleryChangedCallback);
  chrome.test.sendMessage('add_gallery_changed_listener_ok');
}
function addGalleryChangedListener ( ) { chrome . mediaGalleries . onGalleryChanged . addListener ( onGalleryChangedCallback ) ; chrome . test . sendMessage ( 'add_gallery_changed_listener_ok' ) ; }
Helpers to add and remove event listeners.
Helpers to add and remove event listeners .