[Web Payments] UI tweaks to desktop editors

components/payments_strings.grdp

Index: components/payments_strings.grdp
diff --git a/components/payments_strings.grdp b/components/payments_strings.grdp
index 7c6d20cc619e4866acf3b8721f75672c5db449f5..37cf226c0f4e9ba710e0fa63fa44221497d25033 100644
--- a/components/payments_strings.grdp
+++ b/components/payments_strings.grdp
@@ -115,6 +115,9 @@
   <message name="IDS_PAYMENTS_CARD_AND_ADDRESS_SETTINGS_SIGNED_OUT" desc="Label of the section containing the origin description and the link to go to the settings page for card and address options. This label is used when the user is not signed in." formatter_data="android_java">
     Cards and addresses are from Chrome. You can manage them in <ph name="BEGIN_LINK">BEGIN_LINK</ph>Settings<ph name="END_LINK">END_LINK</ph>.
   </message>
+  <message name="IDS_PAYMENTS_CANCEL_PAYMENT" desc="Label of the secondary button in payment request editors. Clicking that button closes the dialog and aborts the payment request completely">
+    Cancel Payment
+  </message>
 
   <!-- Credit Card form -->
   <if expr="is_ios">