WICG/attribution-reporting-api#1111

But do not use them yet. This will make it easier to experiment with
proofs-of-concept for Full Flex prioritization, e.g.
crrev.com/c/5037210, after which we will start using these new functions
in TriggerSpecs::Parse().

This change has no effect on web-visible behavior.

OBSOLETE_HISTOGRAM[Conversions.SourceRegistrationError8]=Replaced by Conversions.SourceRegistrationError9

Bug: 1504219
Change-Id: I78fbcc62071a2b56051e07811ff5ded0d58b2e9c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5049377
Reviewed-by: Robert Sesek <[email protected]>
Reviewed-by: Charlie Harrison <[email protected]>
Commit-Queue: Andrew Paseltiner <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1230803}