Add null check for mProvider

mProvider is null before register is called.
But toString call mProvider.getProviderId() without null check
and caused NullPointerException.
This commit add null check and fix this issue.

Bug: 228796405
Test: m
Change-Id: Ic8e23b21d11705219f1a8fddd544941fbddb183e
2 files changed
tree: f103424d3d4503cfa0b1cd664811eda2e565b670
  1. staticlibs/