Port 5b02a98b

Original Commit Message:

    In the process, convert from a code stub into a builtin.

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

Review-Url: https://codereview.chromium.org/2601243003
Cr-Commit-Position: refs/heads/master@{#41992}