Port 8c7a29b2

Original Commit Message:

    This addresses follow-up comments to https://crrev.com/c/1354887/.

    Use DCHECKs instead of CHECKs and make the branch order consistent
    across architectures.

R=jgruber@chromium.org, joransiu@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: Ic974e31905e15d91efae026837095693f0c01b66
Reviewed-on: https://chromium-review.googlesource.com/c/1365681
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#58104}