Instead of bailing out and assuming everything will be fine if a builtin
hasn't been deserialized yet, deserialize eagerly and perform the full
check.

Change-Id: I60b0d33786a266e124358e2eebe926d8f785881d
Reviewed-on: https://chromium-review.googlesource.com/859998
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50529}