Sometimes we do not have promise on stack, e.g. Promise.reject call,
but we need to attribute this pause with promise rejection.

TBR=yangguo@chromium.org

Bug: chromium:755728
Cq-Include-Trybots: luci.chromium.try:linux_chromium_headless_rel;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I03ca1e1cd6c21677f0a12ece626e2c8a1938437b
Reviewed-on: https://chromium-review.googlesource.com/1249942Reviewed-by: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56293}