FYI I started doing this.

Thank you.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4486435b203881b6163a25f93b9c92812c83478a

commit 4486435b203881b6163a25f93b9c92812c83478a
Author: b.kelemen <b.kelemen@samsung.com>
Date: Mon Jun 20 22:59:35 2016

Remove PaymentResponse.totalAmount according to latest spec

https://github.com/w3c/browser-payment-api/pull/219/commits/f06528fdc71db20867016f29419f2150536a86b5

BUG= 620901 

Review-Url: https://codereview.chromium.org/2072963002
Cr-Commit-Position: refs/heads/master@{#400821}

[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestImpl.java
[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/chrome/android/javatests/src/org/chromium/chrome/browser/payments/PaymentRequestFreeShippingTest.java
[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/chrome/android/javatests/src/org/chromium/chrome/browser/payments/PaymentRequestNoShippingTest.java
[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/chrome/test/data/android/payments/dynamic_shipping.js
[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/chrome/test/data/android/payments/free_shipping.js
[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/chrome/test/data/android/payments/no_shipping.js
[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/third_party/WebKit/LayoutTests/payments/promises-keep-request-alive.html
[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/third_party/WebKit/LayoutTests/webexposed/global-interface-listing-expected.txt
[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/third_party/WebKit/Source/modules/payments/OnPaymentResponseTest.cpp
[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/third_party/WebKit/Source/modules/payments/PaymentResponse.cpp
[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/third_party/WebKit/Source/modules/payments/PaymentResponse.h
[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/third_party/WebKit/Source/modules/payments/PaymentResponse.idl
[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/third_party/WebKit/Source/modules/payments/PaymentResponseTest.cpp
[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/third_party/WebKit/Source/modules/payments/PaymentTestHelper.cpp
[modify] https://crrev.com/4486435b203881b6163a25f93b9c92812c83478a/third_party/WebKit/public/platform/modules/payments/payment_request.mojom