The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0ea8510a570b6556ea40679bb03b64a5fdcc7550

commit 0ea8510a570b6556ea40679bb03b64a5fdcc7550
Author: mathp <mathp@chromium.org>
Date: Wed May 03 00:48:02 2017

[Payments] Desktop: enable the Payment Request integration by default

The WebPayments feature flag is now ENABLED_BY_DEFAULT, and on
the renderer side the feature is enabled based on the same feature.

See blink-dev intent to ship update here: https://groups.google.com/a/chromium.org/forum/#!searchin/blink-dev/Payment$20Request%7Csort:relevance/blink-dev/p1DYoxHlkKg/0mP2L5cyBQAJ

BUG= 717660 
TEST=existing

Review-Url: https://codereview.chromium.org/2855923002
Cr-Commit-Position: refs/heads/master@{#468845}

[modify] https://crrev.com/0ea8510a570b6556ea40679bb03b64a5fdcc7550/chrome/browser/chrome_content_browser_client.cc
[modify] https://crrev.com/0ea8510a570b6556ea40679bb03b64a5fdcc7550/chrome/browser/payments/site_per_process_payments_browsertest.cc
[modify] https://crrev.com/0ea8510a570b6556ea40679bb03b64a5fdcc7550/chrome/browser/ui/views/payments/payment_request_browsertest_base.cc
[modify] https://crrev.com/0ea8510a570b6556ea40679bb03b64a5fdcc7550/chrome/browser/ui/views/payments/payment_request_browsertest_base.h
[modify] https://crrev.com/0ea8510a570b6556ea40679bb03b64a5fdcc7550/content/child/runtime_features.cc
[modify] https://crrev.com/0ea8510a570b6556ea40679bb03b64a5fdcc7550/content/public/common/content_features.cc