commit 0fed7e62bfa0d8351b91d3531228a113637963a3
author Sascha Haeberling <haeberling@google.com> Mon Apr 14 14:41:57 2014 -0700
committer Sascha Haeberling <haeberling@google.com> Mon Apr 14 14:41:57 2014 -0700
tree caa7337b91427a5b29d0bf4c06a65d35abf68bf7
parent e08bc0428d3d5695d029f0b412d98db6ff8ac956

Safeguard callback receiver to prevent crashes.

  Bug: 13765929

It is safe to add these checks here. The receiver is only set in
the constructor, and it's only created in one place, which is
onCreate. And the parameter is the Activity itself, so it can
never be null.
This means the NPE can only happen if onCameraOpened is called after
removeCallbackReceiver is called, which is in onDestroy of the activity.
In this case it's safe to exit.

Change-Id: Ibffd6d54679b564a11b3e83319896241f2e306ad