We're fetching the symbols anyway, so we might as well use those instead in the
preparser.

Change-Id: Ie937c755690cdd7b15e8486aa9680d530eff602e
Reviewed-on: https://chromium-review.googlesource.com/c/1332296Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57460}