root/chrome/browser/extensions/api/media_galleries_private/

[..]
  1. gallery_watch_manager.cc
  2. gallery_watch_manager.h
  3. gallery_watch_state_tracker.cc
  4. gallery_watch_state_tracker.h
  5. media_galleries_private_api.cc
  6. media_galleries_private_api.h
  7. media_galleries_private_event_router.cc
  8. media_galleries_private_event_router.h
  9. media_galleries_watch_apitest.cc
[..]