The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8cf54bd67de7eb5cead851257d32acc8c674913e

commit 8cf54bd67de7eb5cead851257d32acc8c674913e
Author: Rouslan Solomakhin <rouslan@chromium.org>
Date: Mon Aug 27 14:17:46 2018

[Payment Handler] canMakePayment() is true for JIT install.

Before this patch, if the only method of payment available was a payment
handler that is not yet installed, but is available or installation
Just-In-Time (JIT), then PaymentRequest.canMakePayment() would return
"false". This prevented JIT installable payment handler usage by
merchants that don't call PaymentRequest.show() unless
PaymentRequest.canMakePayment() returns true.

This patch makes canMakePayment() return "true" for JIT installable
payment handlers on both desktop and Android. (iOS does not support
payment handlers at this point.)

After this patch, if the only method of payment available is a payment
handler that is not yet installed, but is available for JIT
installation, then PaymentRequest.canMakePayment() would return "true".

Bug:  877644 
Change-Id: I614a02789b514d5d0e7738ca827178a844e74199
Reviewed-on: https://chromium-review.googlesource.com/1188900
Commit-Queue: Rouslan Solomakhin <rouslan@chromium.org>
Reviewed-by: Ganggui Tang <gogerald@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586252}
[modify] https://crrev.com/8cf54bd67de7eb5cead851257d32acc8c674913e/chrome/android/java/src/org/chromium/chrome/browser/payments/ServiceWorkerPaymentApp.java
[modify] https://crrev.com/8cf54bd67de7eb5cead851257d32acc8c674913e/components/payments/content/service_worker_payment_instrument.cc

To verify the fix:

1) Make sure that chrome://flags/#just-in-time-service-worker-payment-app is set to  "Enabled" and restart Chrome, if necessary.

2) Uninstall BobPay payment handler. You can do this by making sure that "https://bobpay.xyz/" says "Install BobPay Web Payment App", which indicates that the payment handler is not installed. If the page says "Uninstall BobPay Web Payment App" instead, then click that link to perform the uninstall.

3) Verify that https://rsolomakhin.github.io/pr/bob/ says "Can make payment" in green text. (Before this patch, the page used to say "Cannot make payment."

The change should be verified on one desktop platform (e.g., Mac) and one Android device, because the code path is slightly different.

Tested this issue on Windows 10, Mac 10.13.6 & Debian Rodate using chrome reported version-70.0.3530.0 & chrome canary-70.0.3535.0 as per C#2.

Followed same steps and able to reproduce the issue on reported version and seems issue got fixed in latest canary. '"Can make payment" text is seen in green color.

As it is working as intended, adding TE Verified labels.

please find the attached screencast for reference.
Thanks..!

Deleted: 877644-Reported -70.0.3530.0.mp4 978 KB

	877644-Reported -70.0.3530.0.mp4 978 KB View Download

Deleted: 877644-Fixed version-70.0.3535.0.mp4 1.7 MB

	877644-Fixed version-70.0.3535.0.mp4 1.7 MB View Download