[Payment Request] Correctly validates and deduplicates URL-based methods.

- Correctly validates and deduplicates the URL-based payment methods
  according to the specs:
  https://www.w3.org/TR/payment-method-id/#dfn-validate-a-url-based-payment-method-identifier
- Also captures the canonical text of the URL instead.

Bug: 602666
Change-Id: I3ba0a8684be1e2e4f769ca551f9cbbf82e3eed36
Reviewed-on: https://chromium-review.googlesource.com/572853
Commit-Queue: mahmadi <mahmadi@chromium.org>
Reviewed-by: Rouslan Solomakhin <rouslan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#487101}
4 files changed