Pbuffers created using eglCreatePbufferFromClientBuffer from share handles
created using keyed mutexes can now have their keyed mutex queried. All other
pbuffers will continue to be created without keyed mutexes.

BUG=337606

Change-Id: Id9039064dd8c89fe1706cc8ecb31111c994761fc
Reviewed-on: https://chromium-review.googlesource.com/324253Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>