Add vendor hook for compaction begin/end. The first use would be to measure compaction durations. Bug: 229927848 Test: local kernel build test Signed-off-by: Robin Hsu <robinhsu@google.com> Change-Id: I3d95434bf49b37199056dc9ddfc36a59a7de17b7 Signed-off-by: Richard Chang <richardycc@google.com> (cherry picked from commit 13b6bd38bb1f43bfffdb08c8f3a4a20d36ccd670)