Add the new API to the internal sync.h file. As there is two different
APIs we will need to discovery dynamically which one to use.
v2: Fix Documentation
Test: Sync unit tests still passes.
Change-Id: I2ab3cd46e48ba5d9c73d54f9583b1a8141566581
This patch moves the legacy API to the internal sync.h header
and add documentation to it.
Test: Sync unit tests still passes.
Change-Id: I9b17eb23af30043b3df5fb9e857affad68ba8521