The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e41979a4ff020142565b9df5922484dee8ce4817

commit e41979a4ff020142565b9df5922484dee8ce4817
Author: Mugdha Lakhani <nator@chromium.org>
Date: Mon Sep 17 13:51:57 2018

[Background Fetch] Implement recordsAvailable.

This has been added to the spec recently:
https://wicg.github.io/background-fetch/#dom-backgroundfetchregistration-recordsavailable
and lets the developer know whether the associated with the fetch are
still accessible.

I've simplified BackgroundFetchContext::CleanupRegistration() and added some
tests.

Bug:  881885 
Change-Id: I7e12002ffd304727f7e538392879a382eed67fa4
Reviewed-on: https://chromium-review.googlesource.com/1216066
Commit-Queue: Mugdha Lakhani <nator@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Rayan Kanso <rayankans@chromium.org>
Reviewed-by: Nasko Oskov <nasko@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#591660}
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/content/browser/background_fetch/background_fetch_context.cc
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/content/browser/background_fetch/background_fetch_registration_notifier.cc
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/content/browser/background_fetch/background_fetch_registration_notifier.h
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/content/browser/background_fetch/background_fetch_registration_notifier_unittest.cc
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/WebKit/LayoutTests/external/wpt/background-fetch/fetch.https.window-expected.txt
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/WebKit/LayoutTests/external/wpt/background-fetch/fetch.https.window.js
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/WebKit/LayoutTests/external/wpt/background-fetch/get.https.window.js
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/WebKit/LayoutTests/external/wpt/background-fetch/idlharness.https.any-expected.txt
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/WebKit/LayoutTests/external/wpt/background-fetch/idlharness.https.any.serviceworker-expected.txt
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/WebKit/LayoutTests/external/wpt/background-fetch/idlharness.https.any.sharedworker-expected.txt
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/WebKit/LayoutTests/external/wpt/background-fetch/idlharness.https.any.worker-expected.txt
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/WebKit/LayoutTests/http/tests/serviceworker/webexposed/global-interface-listing-service-worker-expected.txt
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/WebKit/LayoutTests/webexposed/global-interface-listing-dedicated-worker-expected.txt
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/WebKit/LayoutTests/webexposed/global-interface-listing-expected.txt
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/WebKit/LayoutTests/webexposed/global-interface-listing-shared-worker-expected.txt
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/blink/public/platform/modules/background_fetch/background_fetch.mojom
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/blink/renderer/modules/background_fetch/background_fetch_registration.cc
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/blink/renderer/modules/background_fetch/background_fetch_registration.h
[modify] https://crrev.com/e41979a4ff020142565b9df5922484dee8ce4817/third_party/blink/renderer/modules/background_fetch/background_fetch_registration.idl

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8cf0805e0ef62bbc2f36d4b3c5b54b66ac4f73bf

commit 8cf0805e0ef62bbc2f36d4b3c5b54b66ac4f73bf
Author: Mugdha Lakhani <nator@chromium.org>
Date: Mon Sep 17 15:34:28 2018

[Background Fetch] Remove AddGarbageCollectionCallback.

https://chromium-review.googlesource.com/c/chromium/src/+/1216066
removed the usage of AddGarbageCollectionCallback.
This CL removes the implementation + unit test.

Bug:  881885 
Change-Id: I1d1b066b9596c1174ad4fafc46b057fbab322ff0
Reviewed-on: https://chromium-review.googlesource.com/1216068
Commit-Queue: Mugdha Lakhani <nator@chromium.org>
Reviewed-by: Rayan Kanso <rayankans@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#591684}
[modify] https://crrev.com/8cf0805e0ef62bbc2f36d4b3c5b54b66ac4f73bf/content/browser/background_fetch/background_fetch_registration_notifier.cc
[modify] https://crrev.com/8cf0805e0ef62bbc2f36d4b3c5b54b66ac4f73bf/content/browser/background_fetch/background_fetch_registration_notifier.h
[modify] https://crrev.com/8cf0805e0ef62bbc2f36d4b3c5b54b66ac4f73bf/content/browser/background_fetch/background_fetch_registration_notifier_unittest.cc