BUG=v8:6389,v8:6379,v8:6409

Change-Id: I24e0c8b6212f2cf2877d52f27eca0beb133afa1e
Reviewed-on: https://chromium-review.googlesource.com/508348Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45394}