PaymentRequest: Provide shippingAddress in PaymentResponse.

The shippingAddress attribute was already added by this issue[1] but current
implementation isn't supporting the attribute yet. So, we should provide the
attribute in PaymentResponse.

[1] https://github.com/w3c/browser-payment-api/pull/139

BUG=617194

Review-Url: https://codereview.chromium.org/2038333002
Cr-Commit-Position: refs/heads/master@{#398058}
6 files changed