Added video calling data usage per-uid support

Now the VT call data usage will be counted under
current dialer's data usage as well as the total
device data usage.

Test: Manual
bug: 37671326

Merged-In: I8351e9ae17c84210f7ca6c319d3bddcbb0043341
Change-Id: I8351e9ae17c84210f7ca6c319d3bddcbb0043341