PaymentHandler: Implement requestPermission().

components/payments_strings.grdp

Index: components/payments_strings.grdp
diff --git a/components/payments_strings.grdp b/components/payments_strings.grdp
index 0c663a06f23b61c486f54448eae617dc90f20458..2a10a16f57e84810b867bf3bab172f40f2e3e3f7 100644
--- a/components/payments_strings.grdp
+++ b/components/payments_strings.grdp
@@ -310,6 +310,11 @@
     </message>
   </if>
 
+  <!-- PaymentHandler API -->
+  <message name="IDS_PAYMENTS_PAYMENT_HANDLER_REQUEST_PERMISSION" desc="requestPermission">
+    Chromium needs permission to install a new payment app provided from this site.

[please use gerrit instead, 2017/06/20 13:28:09]

"Chromium" in strings should be used inside of <if expr="not _google_chrome">.
Please also add a string for "Chrome".

[zino, 2017/06/22 17:26:46]

I'll wait for a new string. (as per crbug's comments)

+  </message>
+
   <!-- Payment Request section preview strings. They are slightly different on desktop and android because the pluralization and formatting code behaves differently. -->
   <if expr="not is_android">
     <message name="IDS_PAYMENT_REQUEST_PAYMENT_METHODS_PREVIEW" desc="This is a snippet of a payment method a user has saved to Chrome, plus an indication of the number of additional payment methods the user has saved. Its function is to show the user has payment methods that can be used to complete a payment, and thus doesn't have to type the entire payment method. [ICU Syntax]">