The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/177ba2b6cc83d1d14db9636e8b751ee7fcf4acee

commit 177ba2b6cc83d1d14db9636e8b751ee7fcf4acee
Author: Rayan Kanso <rayankans@chromium.org>
Date: Thu Sep 27 14:18:58 2018

[Background Fetch] Enforce active registration limit per origin.

Set a per-origin limit (5) for how many active background fetch
registrations an origin can have.

This is to avoid a potential abuse vector until a more concrete
permission model is in place. With this, an origin can't keep
registering fetches and permanently have a notification shown, also
blocking other origins from starting a background fetch.

Bug: 889401
Change-Id: I9aeac7121c46ffdd3910b3b891051e9c4951bc6e
Reviewed-on: https://chromium-review.googlesource.com/1245369
Commit-Queue: Rayan Kanso <rayankans@chromium.org>
Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594712}
[modify] https://crrev.com/177ba2b6cc83d1d14db9636e8b751ee7fcf4acee/content/browser/background_fetch/background_fetch_data_manager_unittest.cc
[modify] https://crrev.com/177ba2b6cc83d1d14db9636e8b751ee7fcf4acee/content/browser/background_fetch/background_fetch_service_unittest.cc
[modify] https://crrev.com/177ba2b6cc83d1d14db9636e8b751ee7fcf4acee/content/browser/background_fetch/background_fetch_test_base.cc
[modify] https://crrev.com/177ba2b6cc83d1d14db9636e8b751ee7fcf4acee/content/browser/background_fetch/background_fetch_test_base.h
[modify] https://crrev.com/177ba2b6cc83d1d14db9636e8b751ee7fcf4acee/content/browser/background_fetch/storage/create_metadata_task.cc
[modify] https://crrev.com/177ba2b6cc83d1d14db9636e8b751ee7fcf4acee/content/browser/background_fetch/storage/create_metadata_task.h
[modify] https://crrev.com/177ba2b6cc83d1d14db9636e8b751ee7fcf4acee/content/browser/service_worker/service_worker_context_wrapper.cc
[modify] https://crrev.com/177ba2b6cc83d1d14db9636e8b751ee7fcf4acee/content/browser/service_worker/service_worker_context_wrapper.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/933c4c53594e3c66256f63a4f9fec46f7524d816

commit 933c4c53594e3c66256f63a4f9fec46f7524d816
Author: Rayan Kanso <rayankans@chromium.org>
Date: Tue Oct 02 18:53:12 2018

[Background Fetch] Report registration limit error to developers.

Adds a BackgroundFetchError which is propagated to the developer.

Bug: 889401
Change-Id: Ie4505cd0f50ab263cce5d66c854094133bc3539c
Reviewed-on: https://chromium-review.googlesource.com/1246102
Commit-Queue: Rayan Kanso <rayankans@chromium.org>
Reviewed-by: Mugdha Lakhani <nator@chromium.org>
Reviewed-by: Ken Buchanan <kenrb@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595933}
[modify] https://crrev.com/933c4c53594e3c66256f63a4f9fec46f7524d816/content/browser/background_fetch/background_fetch_data_manager_unittest.cc
[modify] https://crrev.com/933c4c53594e3c66256f63a4f9fec46f7524d816/content/browser/background_fetch/storage/create_metadata_task.cc
[add] https://crrev.com/933c4c53594e3c66256f63a4f9fec46f7524d816/third_party/WebKit/LayoutTests/http/tests/background_fetch/fetch.https.html
[modify] https://crrev.com/933c4c53594e3c66256f63a4f9fec46f7524d816/third_party/blink/public/platform/modules/background_fetch/background_fetch.mojom
[modify] https://crrev.com/933c4c53594e3c66256f63a4f9fec46f7524d816/third_party/blink/renderer/modules/background_fetch/background_fetch_manager.cc
[modify] https://crrev.com/933c4c53594e3c66256f63a4f9fec46f7524d816/third_party/blink/renderer/modules/background_fetch/background_fetch_registration.cc
[modify] https://crrev.com/933c4c53594e3c66256f63a4f9fec46f7524d816/third_party/blink/renderer/modules/background_fetch/background_fetch_update_ui_event.cc
[modify] https://crrev.com/933c4c53594e3c66256f63a4f9fec46f7524d816/tools/metrics/histograms/enums.xml