GitLab

This is one step in unifying LazyContextTaskQueue::PendingTask and LazyBackgroundTaskQueue::PendingTask.

Change-Id: Icf383aa3a3c91a7b9e371cef7a2ee24c8dd55c1d
Reviewed-on: https://chromium-review.googlesource.com/c/1347734
Commit-Queue: David Bertoni <dbertoni@chromium.org>
Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611382}