Merge "simpleperf: refactor SampleTree for reuse." am: c8642b2dcf
am: 1588c2ff30

* commit '1588c2ff30418f4df6d7b50251d232e8acdccc9d':
  simpleperf: refactor SampleTree for reuse.

Change-Id: Ie1c21522bb52f30cb0817574bfa9fa0c0ed5bdf9