The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/52d1b6cb327eaa9ef4fad76ccb7f1b54276ba5b8

commit 52d1b6cb327eaa9ef4fad76ccb7f1b54276ba5b8
Author: Vlad Tsyrklevich <vtsyrklevich@chromium.org>
Date: Mon Aug 21 21:21:30 2017

Enable ThinLTO for the ClusterFuzz CFI bot

The CF buildbot currently builds using monolithic LTO which is slower
and does not match the release build which uses ThinLTO.

Bug:  757039 
Change-Id: Id23e1a10314913413574c000497d01667e2d2798
Reviewed-on: https://chromium-review.googlesource.com/621950
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Peter Collingbourne <pcc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#496063}
[modify] https://crrev.com/52d1b6cb327eaa9ef4fad76ccb7f1b54276ba5b8/tools/mb/mb_config.pyl