Wifi: Check for WiFiService's existence before its access

The sip components currently access WiFiManager before it is started.
The current behavior is to not start the WiFi service during the FDE
encryption (WiFi service is not considered as a core service). This
behavior would lead to a fatal exception. Address this by adding a NULL
check before the access in all the components of telephony framework.

See also the similar CAF change in frameworks/base:
I5fb753df8874b962622ef6921b9cbc518381203c

Issue: FP2P-373
Change-Id: Idad86aebf677aefe3905e26d77cb087686ed2634
2 files changed
tree: cdf809a701647513a933f631d1433399dd1a157f
  1. src/
  2. Android.bp
  3. CleanSpec.mk