Hi Hwi, here is a video of the proposed UI implementation for this. Could you review it? Thanks?

Deleted: expiration_cc.mp4 2.6 MB

	expiration_cc.mp4 2.6 MB View Download

Thanks for looking into the issue, sebsb@!

Wondering:

1) Show the current month & year by default
2) Don't validate month yet until year is selected or the user select moves to other field
3) Validate month & year once year is selected or the user select moves to other field
4) Show error message underneath the month selector in the same style as we use on card number

Deleted: Expiration validation.png 310 KB

	Expiration validation.png 310 KB View Download

Interesting, thanks for reviewing. One important info, you cannot set a year in the past. That's why I initially put the error in the month, because 2016 could be a valid expiration year. Please tell me what you think.

I like your idea of selecting the current month. That way, the expiration we suggest by default is actually valid :)

Gotcha. Please ignore c#2.

I'm trying to minimize error messages while the user is still selecting for the first time around.

Here's another attempt:

1) Do not pre-select Month and Year
2) Validate until both Month and Year are selected regardless of selection order
3) Underline both in red and show an error message

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	Expiration validation.png 304 KB View Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9517dee1565a1629116b9e30c43c75ba65d510cb

commit 9517dee1565a1629116b9e30c43c75ba65d510cb
Author: sebsg <sebsg@chromium.org>
Date: Thu Oct 27 22:19:15 2016

[Payments] Don't add expired cards in Payment Request.

BUG= 658823 

Review-Url: https://codereview.chromium.org/2451303002
Cr-Commit-Position: refs/heads/master@{#428164}

[modify] https://crrev.com/9517dee1565a1629116b9e30c43c75ba65d510cb/chrome/android/java/src/org/chromium/chrome/browser/payments/CardEditor.java
[modify] https://crrev.com/9517dee1565a1629116b9e30c43c75ba65d510cb/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestImpl.java
[modify] https://crrev.com/9517dee1565a1629116b9e30c43c75ba65d510cb/chrome/android/java/src/org/chromium/chrome/browser/payments/ui/EditorFieldModel.java
[modify] https://crrev.com/9517dee1565a1629116b9e30c43c75ba65d510cb/chrome/android/java/strings/android_chrome_strings.grd
[modify] https://crrev.com/9517dee1565a1629116b9e30c43c75ba65d510cb/chrome/android/javatests/src/org/chromium/chrome/browser/payments/PaymentRequestExpiredLocalCardTest.java
[modify] https://crrev.com/9517dee1565a1629116b9e30c43c75ba65d510cb/chrome/android/javatests/src/org/chromium/chrome/browser/payments/PaymentRequestTestBase.java

Would like to merge to M-55.

Your change meets the bar and is auto-approved for M55 (branch: 2883)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0c15050c3afeaea53612aebc04e0551fc70ef18b

commit 0c15050c3afeaea53612aebc04e0551fc70ef18b
Author: Rouslan Solomakhin <rouslan@chromium.org>
Date: Tue Nov 01 21:22:00 2016

[Merge M-55] [Payments] Don't add expired cards in Payment Request.

BUG= 658823 

Review-Url: https://codereview.chromium.org/2451303002
Cr-Commit-Position: refs/heads/master@{#428164}
(cherry picked from commit 9517dee1565a1629116b9e30c43c75ba65d510cb)

Review URL: https://codereview.chromium.org/2469103002 .

Cr-Commit-Position: refs/branch-heads/2883@{#408}
Cr-Branched-From: 614d31daee2f61b0180df403a8ad43f20b9f6dd7-refs/heads/master@{#423768}

[modify] https://crrev.com/0c15050c3afeaea53612aebc04e0551fc70ef18b/chrome/android/java/src/org/chromium/chrome/browser/payments/CardEditor.java
[modify] https://crrev.com/0c15050c3afeaea53612aebc04e0551fc70ef18b/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestImpl.java
[modify] https://crrev.com/0c15050c3afeaea53612aebc04e0551fc70ef18b/chrome/android/java/src/org/chromium/chrome/browser/payments/ui/EditorFieldModel.java
[modify] https://crrev.com/0c15050c3afeaea53612aebc04e0551fc70ef18b/chrome/android/java/strings/android_chrome_strings.grd
[add] https://crrev.com/0c15050c3afeaea53612aebc04e0551fc70ef18b/chrome/android/javatests/src/org/chromium/chrome/browser/payments/PaymentRequestExpiredLocalCardTest.java
[modify] https://crrev.com/0c15050c3afeaea53612aebc04e0551fc70ef18b/chrome/android/javatests/src/org/chromium/chrome/browser/payments/PaymentRequestTestBase.java