Reading through some code today I happened to notice a few places where
we were passing "ok" instead of "CHECK_OK", leading to the possibility
of code continuing on past a syntax error. This fixes all such
cases I found (through manual inspection) in parser-base.h

Change-Id: I95ef0a08d0e0a537d86a73bb62929842a3f57a31
Reviewed-on: https://chromium-review.googlesource.com/c/1262998
Commit-Queue: Adam Klein <adamk@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56452}