GitLab

*Allow empty alias names (indicates that a service does not exist).
*Add the "mandatory" service param. Also added an IsCompatible() method
 to indicate if any listed keys are not handled by the parser. Normally
 I would consider that level of handling to be higher level than the
 wire-format stuff the parser should deal with, but the parser is the
 code that knows what params it can handle.
*Also added some extra IP hint validation in the fuzzer while I was
 poking at it for the other changes.

Bug: 1138620
Change-Id: I8172fb5cc9b6ba06d42e6f68c2d11517115f80e2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2508429Reviewed-by: Dan McArdle <dmcardle@chromium.org>
Commit-Queue: Eric Orth <ericorth@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823281}