Notify NetworkPolicyManagerService on tethering changes

(cherry-pick of d73faf07606d40d3915d22a72fa14f7ba956d459)

No longer do this in ConnectivityService#tether/untether.
Instead, have Tethering do it when an interface is actually
tethered.

Bug: 31405407
Test: Toggling hotspot now disables data saver

Change-Id: I9910a2e488c30c92d45f817c8f5df0fac5510de6
1 file changed
tree: 843d5895a53165e450eb60ca9f7d66274ca503f2
  1. core/
  2. services/
  3. tests/