Port 9302db48

Original Commit Message:

    Merging the temporary HeapObjectPtr back into HeapObject.

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

Change-Id: I4f92282b7b4c66bb73da30e076a8378e0cf24836
Reviewed-on: https://chromium-review.googlesource.com/c/1394813Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#58534}