rayankans@ Could you please look into this issue.

kkaluri@,

Fix for 71 is in https://chromium-review.googlesource.com/c/chromium/src/+/1344030, try bots were flaky yesterday and I couldn't submit.

I tested the change on ChromeOS from head, and merged into the 71 branch, and it's working as expected.

I'll request a merge into 71 after it's been submitted

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3d7e92aff63d99b16b13af55ce88f438a2d9f9ed

commit 3d7e92aff63d99b16b13af55ce88f438a2d9f9ed
Author: Rayan Kanso <rayankans@google.com>
Date: Wed Nov 21 09:58:38 2018

[Background Fetch] Fix ChromeOS delegate bug.

ChromeOS was creating multiple BackgroundFetchDelegate clients, and
overwriting the client initiating the fetches.

The fix was to check that we are not overwriting the client. This fixes
our problems in the short term, and a longer term fix is planned in
 crbug.com/907075 .

The fix works on ChromeOS head, as well as 71 (tested via manually
merging the change).

Bug: 907038
Change-Id: Ic1d5bc9f55b22359aa592c71f49d8ab5ed90de5e
Reviewed-on: https://chromium-review.googlesource.com/c/1344030
Commit-Queue: Rayan Kanso <rayankans@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609975}
[modify] https://crrev.com/3d7e92aff63d99b16b13af55ce88f438a2d9f9ed/content/browser/background_fetch/background_fetch_delegate_proxy.cc

Requesting merge into 71. The change hasn't hit canary yet, but it only affects ChromeOS, so I manually merged it into 71 locally, built it, and made sure it is WAI.

This bug requires manual review: We are only 12 days from stable.
Please contact the milestone owner if you have questions.
Owners: benmason@(Android), kariahda@(iOS), kbleicher@(ChromeOS), govind@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

+ geohsu@ &  kbleicher@ for M71 merge review as this change only affects Chrome OS per comment #4.

Approved for M71 ChromeOS

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4d0b46f1e0e8abb4a1ea247ad5a8a2e292f708af

commit 4d0b46f1e0e8abb4a1ea247ad5a8a2e292f708af
Author: Rayan Kanso <rayankans@google.com>
Date: Wed Nov 21 16:43:03 2018

[Background Fetch] Fix ChromeOS delegate bug.

ChromeOS was creating multiple BackgroundFetchDelegate clients, and
overwriting the client initiating the fetches.

The fix was to check that we are not overwriting the client. This fixes
our problems in the short term, and a longer term fix is planned in
 crbug.com/907075 .

The fix works on ChromeOS head, as well as 71 (tested via manually
merging the change).

Bug: 907038
Change-Id: Ic1d5bc9f55b22359aa592c71f49d8ab5ed90de5e
Reviewed-on: https://chromium-review.googlesource.com/c/1344030
Commit-Queue: Rayan Kanso <rayankans@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#609975}(cherry picked from commit 3d7e92aff63d99b16b13af55ce88f438a2d9f9ed)
Reviewed-on: https://chromium-review.googlesource.com/c/1346464
Cr-Commit-Position: refs/branch-heads/3578@{#787}
Cr-Branched-From: 4226ddf99103e493d7afb23a4c7902ee496108b6-refs/heads/master@{#599034}
[modify] https://crrev.com/4d0b46f1e0e8abb4a1ea247ad5a8a2e292f708af/content/browser/background_fetch/background_fetch_delegate_proxy.cc

The following revision refers to this bug: 
https://chromium.googlesource.com/chromium/src.git/+/4d0b46f1e0e8abb4a1ea247ad5a8a2e292f708af

Commit: 4d0b46f1e0e8abb4a1ea247ad5a8a2e292f708af
Author: rayankans@google.com
Commiter: rayankans@chromium.org
Date: 2018-11-21 16:43:03 +0000 UTC

[Background Fetch] Fix ChromeOS delegate bug.

ChromeOS was creating multiple BackgroundFetchDelegate clients, and
overwriting the client initiating the fetches.

The fix was to check that we are not overwriting the client. This fixes
our problems in the short term, and a longer term fix is planned in
 crbug.com/907075 .

The fix works on ChromeOS head, as well as 71 (tested via manually
merging the change).

Bug: 907038
Change-Id: Ic1d5bc9f55b22359aa592c71f49d8ab5ed90de5e
Reviewed-on: https://chromium-review.googlesource.com/c/1344030
Commit-Queue: Rayan Kanso <rayankans@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#609975}(cherry picked from commit 3d7e92aff63d99b16b13af55ce88f438a2d9f9ed)
Reviewed-on: https://chromium-review.googlesource.com/c/1346464
Cr-Commit-Position: refs/branch-heads/3578@{#787}
Cr-Branched-From: 4226ddf99103e493d7afb23a4c7902ee496108b6-refs/heads/master@{#599034}

kkaluri@, I merged the fix, can you confirm on the master bug that this is fixed after you get a chance to check it? Assigning this bug to you in the meanwhile, thanks!

Verified this issue on Chrome_OS/Google_Kip.5216.227.152 with chrome #71.0.3578.66 and observed that Pause, Resume & Cancel functionalities are working as intended.