Merge "simpleperf: refactor SampleTree for reuse."
am: c8642b2dcf

* commit 'c8642b2dcfd60f12a0cdbd1f9361967d264d2a3a':
  simpleperf: refactor SampleTree for reuse.

Change-Id: Ic5e6544480e0e898467c72401ccf8374b1542807