Convert away from method JSONReader::ReadDeprecated

Replace usage to instead use JSONReader::Read that returns a
base::Optional<base::Value>.

Also rename PaymentResponseToDictionaryValue after changing
the return type to base::Value (to use the new API).

Bug: 925165, 646113
Change-Id: Ie88068c76f810dff08e8ec36230d0154c6f9effa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1503329
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Moe Ahmadi <mahmadi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638063}
4 files changed