Good idea. If you start working on this, assign to yourself and mark as "Started." (If I start working on this, I will mark as "Started" as well.)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/92c5d3d1a1c2659c20c9ac7eb2e5de90c2199f0b

commit 92c5d3d1a1c2659c20c9ac7eb2e5de90c2199f0b
Author: sanjoy.pal <sanjoy.pal@samsung.com>
Date: Fri Jul 22 06:37:00 2016

Add a timeout to the update event in case page doesn't resolve promise from updateWith

Specification:
https://www.w3.org/TR/payment-request/#updatewith

BUG= 629462 

Review-Url: https://codereview.chromium.org/2170783002
Cr-Commit-Position: refs/heads/master@{#407082}

[modify] https://crrev.com/92c5d3d1a1c2659c20c9ac7eb2e5de90c2199f0b/third_party/WebKit/Source/modules/payments/PaymentRequestUpdateEvent.cpp
[modify] https://crrev.com/92c5d3d1a1c2659c20c9ac7eb2e5de90c2199f0b/third_party/WebKit/Source/modules/payments/PaymentRequestUpdateEvent.h
[modify] https://crrev.com/92c5d3d1a1c2659c20c9ac7eb2e5de90c2199f0b/third_party/WebKit/Source/modules/payments/PaymentRequestUpdateEventTest.cpp

rouslan@ Currently exception message printed in this case on the console is
"DOMException: The user aborted a request"

Will it be better to print something like
"Timed out as page didn't resolve/reject promise from change event"

Good idea. Let's do it. If you start working on it, please mark the bug "Started". 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f1b534bc924aa095cc581b4524c4890629b9c633

commit f1b534bc924aa095cc581b4524c4890629b9c633
Author: sanjoy.pal <sanjoy.pal@samsung.com>
Date: Mon Aug 01 17:02:57 2016

Print proper debug message in case of change event timeout.

"AbortError: Timed out as the page didn't resolve the promise
from change event"

BUG= 629462 

Review-Url: https://codereview.chromium.org/2193183002
Cr-Commit-Position: refs/heads/master@{#408986}

[modify] https://crrev.com/f1b534bc924aa095cc581b4524c4890629b9c633/third_party/WebKit/Source/modules/payments/PaymentRequest.cpp
[modify] https://crrev.com/f1b534bc924aa095cc581b4524c4890629b9c633/third_party/WebKit/Source/modules/payments/PaymentRequest.h
[modify] https://crrev.com/f1b534bc924aa095cc581b4524c4890629b9c633/third_party/WebKit/Source/modules/payments/PaymentRequestTest.cpp
[modify] https://crrev.com/f1b534bc924aa095cc581b4524c4890629b9c633/third_party/WebKit/Source/modules/payments/PaymentRequestUpdateEvent.cpp
[modify] https://crrev.com/f1b534bc924aa095cc581b4524c4890629b9c633/third_party/WebKit/Source/modules/payments/PaymentRequestUpdateEventTest.cpp
[modify] https://crrev.com/f1b534bc924aa095cc581b4524c4890629b9c633/third_party/WebKit/Source/modules/payments/PaymentUpdater.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/16ba70a3e0d4996af6c60412092762447ae69020

commit 16ba70a3e0d4996af6c60412092762447ae69020
Author: sanjoy.pal <sanjoy.pal@samsung.com>
Date: Tue Sep 27 07:16:28 2016

Properly name the timeout callback for update event.

Making timer callback public for testing as per Marijn's comment in https://codereview.chromium.org/2192413002/.

BUG= 629462 

Review-Url: https://codereview.chromium.org/2222883002
Cr-Commit-Position: refs/heads/master@{#421135}

[modify] https://crrev.com/16ba70a3e0d4996af6c60412092762447ae69020/third_party/WebKit/Source/modules/payments/PaymentRequestUpdateEvent.cpp
[modify] https://crrev.com/16ba70a3e0d4996af6c60412092762447ae69020/third_party/WebKit/Source/modules/payments/PaymentRequestUpdateEvent.h
[modify] https://crrev.com/16ba70a3e0d4996af6c60412092762447ae69020/third_party/WebKit/Source/modules/payments/PaymentRequestUpdateEventTest.cpp