GitLab

We currently wake the browser up and call FireReadyEvents() to fire any
ready sync events, and then call the passed |callback|. Before this
change, we were invoking the callback once all sync events had been
fired. This CL waits till all those sync events have completed before
running the callback.

This will have the effect of keeping the browser awake until all sync
events complete, and will add a few minutes to how long we hold the
wakelock. It will give the browser a chance to finish processing
(Periodic) Background Sync registrations and reduce the number of times
we need to wake the browser up.

This CL adds a new parameter to BackgroundSyncParameters to enable this
functionality, so that we can run experiments using the existing
'BackgroundSync' field trial before it's enabled everywhere.

A unit test has also been added to verify the functionality.

Bug: 933849, 932591
Change-Id: Ica68f6bdb262dea2365334296ae825d91126c65b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1807194
Commit-Queue: Mugdha Lakhani <nator@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Reviewed-by: Rayan Kanso <rayankans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#704489}