Revert 175938

Revert 175938
> [Media Galleries] Add an ImageCaptureCore listener for Mac. (part 2)
> 
> This listener uses the ImageCapture API to watch for attach and detach
> events of PTP devices and other devices which can be read through the
> library. It forwards such notifications through the SystemMonitor.
> 
> Also provides an API for clients to access such devices directly and
> retrieve the media contents from them.
> 
> R=thestig@chromium.org,sail@chromium.org
> BUG=151681
> 
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=175471
> 
> Review URL: https://chromiumcodereview.appspot.com/11442057

TBR=gbillock@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=175943