tree fcf87a28eed4ce0a72e9ece786fcad55c66ebfef
parent f822eda51b9c1fa7f69b56d0ff26a148503a20b8
author Yangster-mac <yanglu@google.com> 1513061749 -0800
committer Yangster-mac <yanglu@google.com> 1513385609 -0800

Stats log api for attribution chain.

Test: all unit test passed.
Change-Id: I628d409e517f4f95c8da1d0c7fd4d514c1d9196d