Add a new hidden event PhoneCapabilityChanged that can be
listned to know phone capability has changed.

Bug: 92796390
Test: build
Change-Id: I12ccde1a1c4257ac50c2cfa73d2d5b58dd7e1518
Merged-In: I12ccde1a1c4257ac50c2cfa73d2d5b58dd7e1518