BUG=v8:6379

Change-Id: Ieddf861db3e5ef0445989c25ba5ee36f47c0d1bf
Reviewed-on: https://chromium-review.googlesource.com/506155
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45343}