tree 1b6ee3d35b702041aabe0d6b69d375dfcc0fe468
parent b172e4a6b35588728f17008e3510eebff95cc38c
author Gary Morain <gmorain@chromium.org> 1335559721 -0700
committer Gerrit <chrome-bot@google.com> 1335563304 -0700

shill: Do not run OnScanReply callback if it is null

For GSM, the current implementation of Cellular::Scan passes
callback that has not been bound to a method.  OnScanReply tries
to run the callback, resulting in a seg fault.  This change checks
for null before running the callback.

BUG=None
TEST=Ran all unit tests.  Manual: Before logging in, do a mobile scan.
Verify that the scan completes and shill does not crash.

Change-Id: Ib6115892cf180bd7aeb237de8605dd89f81137b9
Reviewed-on: https://gerrit.chromium.org/gerrit/21384
Reviewed-by: Jason Glasgow <jglasgow@chromium.org>
Commit-Ready: Gary Morain <gmorain@chromium.org>
Tested-by: Gary Morain <gmorain@chromium.org>