Oh, did you already start this work?

Yes, I started it ~15 hours ago :-)

Work in progress @ http://crrev.com/2048823004

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e411df45423c6c1fd6acb338ce0ea48630784b18

commit e411df45423c6c1fd6acb338ce0ea48630784b18
Author: rouslan <rouslan@chromium.org>
Date: Wed Jun 15 06:48:34 2016

PaymentRequest.abort() should return a promise.

The abort() method on an instance of PaymentRequest returns a promise
that is resolved when the browser has hidden its UI. If the browser is
unable to abort payment, then the abort() promise is rejected. This can
happen, for example, when the browser has launched a 3rd-party payment
app and is unable to abort it.

PaymentRequest interface:
https://w3c.github.io/browser-payment-api/specs/paymentrequest.html#paymentrequest-interface

The abort() method:
https://w3c.github.io/browser-payment-api/specs/paymentrequest.html#abort

The pull request that introduced the promise:
https://github.com/w3c/browser-payment-api/pull/190/files

Additional changes in this patch:
  * Move abort() tests into AbortTest.cpp
  * Move common test fixture into PaymentRequestTestBase.h/cpp.
  * Actually fail tests if MockFunction is not called as expected.
  * Fix RejectShowPromiseWithRequestShippingFalseAndShippingAddressInResponse

BUG= 617193 

Review-Url: https://codereview.chromium.org/2048823004
Cr-Commit-Position: refs/heads/master@{#399854}

[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/chrome/android/BUILD.gn
[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/chrome/android/chrome_apk.gyp
[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/chrome/android/java/src/org/chromium/chrome/browser/autofill/CardUnmaskBridge.java
[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/chrome/android/java/src/org/chromium/chrome/browser/autofill/CardUnmaskPrompt.java
[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestImpl.java
[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/chrome/android/java/src/org/chromium/chrome/browser/payments/ui/PaymentRequestUI.java
[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/chrome/android/java_sources.gni
[add] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/chrome/android/javatests/src/org/chromium/chrome/browser/payments/PaymentRequestAbortTest.java
[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/chrome/android/javatests/src/org/chromium/chrome/browser/payments/PaymentRequestTestBase.java
[add] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/chrome/test/data/android/payments/abort.js
[add] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/chrome/test/data/android/payments/payment_request_abort_test.html
[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/third_party/WebKit/LayoutTests/payments/payment-request-interface.html
[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/third_party/WebKit/Source/modules/modules.gypi
[add] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/third_party/WebKit/Source/modules/payments/AbortTest.cpp
[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/third_party/WebKit/Source/modules/payments/PaymentRequest.cpp
[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/third_party/WebKit/Source/modules/payments/PaymentRequest.h
[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/third_party/WebKit/Source/modules/payments/PaymentRequest.idl
[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/third_party/WebKit/Source/modules/payments/PaymentRequestTest.cpp
[add] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/third_party/WebKit/Source/modules/payments/PaymentRequestTestBase.cpp
[add] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/third_party/WebKit/Source/modules/payments/PaymentRequestTestBase.h
[modify] https://crrev.com/e411df45423c6c1fd6acb338ce0ea48630784b18/third_party/WebKit/public/platform/modules/payments/payment_request.mojom