SF: VSyncReactor add hwvsync ingestion functions

Adds 3 more functions from the DispSync interface to VSyncReactor,
{begin,end}Resync (not needed), and addResyncSample.

Bug: 140303479
Test: 2 new units
Change-Id: I8b1cb6991f89ce7910a144c350f12ceda82ca129
3 files changed