The DCHECK is supposed to check that the read in the next line does not
read out of bounds. Hence we have to use {pc} and not {pc_}.
I accidentally triggered this while writing an unrelated test case, but
now fail to reproduce.

R=ahaas@chromium.org

Change-Id: Ia3fa9a9874866dc14180b22b9af526459fbda495
Reviewed-on: https://chromium-review.googlesource.com/568487Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46621}