Safely read carrier config.

There were problems reading carrier config from a secondary user (where
the com.android.phone process is empty) and also problems running a
second instance of CarrierConfigLoader. However, the secondary user can
talk to the main CarrierConfigLoader through the public API.

Bug: 21334821
Bug: 22108473
Change-Id: I127dbb8453d4bb24548cacdfb27ba44879ca4b33
1 file changed