[Mac] Enumerate webcam devices on the main thread.

[Mac] Enumerate webcam devices on the main thread.

The associated bug is about a crash in code which is only loaded due
to +deviceNames, though the crash does not have any such code on the
stack.  If that call were not thread-safe, then possibly using it on a
different thread breaks assumptions about where things are allocated
and released.

BUG=139164
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=161024

[Scott Hess - ex-Googler, 2012-10-09 23:42:24]

This one is also easy to put on the main thread.  WDYT?

This would foul the waters WRT your breakpad key.  If the crash keeps happening
with this change, then your breakpad key is still interesting.  If the crash
stops, then we won't see your breakpad key associated with it.  So I don't think
it ruins anything, but my logic is known to be faulty.

[wjia(left Chromium), 2012-10-09 23:49:41]

lgtm

[sail, 2012-10-09 23:53:39]

LGTM!

https://codereview.chromium.org/11017045/diff/1/media/video/capture/mac/video...
File media/video/capture/mac/video_capture_device_qtkit_mac.mm (right):

https://codereview.chromium.org/11017045/diff/1/media/video/capture/mac/video...
media/video/capture/mac/video_capture_device_qtkit_mac.mm:28: + (NSDictionary
*)deviceNames {
no space before *

[commit-bot: I haz the power, 2012-10-09 23:58:20]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/shess@chromium.org/11017045/5001

[commit-bot: I haz the power, 2012-10-10 02:45:27]

Change committed as 161024