[iOS] Fix crash in QR scanning code when no camera is available

The deallocation code in CameraController assumes that all the setup
has been done. If there is no camera, much of this setup hasn't been
done, so we should skip it.

Bug: 941714
Change-Id: Icbbd75ccf988f08b3178869dd91b63b8413a7b7b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1523389
Commit-Queue: Robbie Gibson <rkgibson@google.com>
Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#640759}
1 file changed