On test failures, the bots compare the results of V8 Tip-of-Tree with Chromium's pinned V8 version, to only flag newly introduced V8 problems (with false positives <<5%). Blame assignment is trivial as the Linux release bot tests all revisions.
Commits with newly introduced failures are normally reverted to unblock auto-rolling into Chromium. In case you break layout tests and the changes are expected, follow this procedure:
[ Failure Pass ]for the changed tests (more).
[ Failure Pass ]to
[ NeedsRebaseline ]in Chromium. Tests will be automatically rebaselined.
Please associate all CLs with a BUG.