[Payments] Implement openWindow for service worker based payment handler

third_party/WebKit/Source/modules/payments/PaymentRequestEvent.idl

Index: third_party/WebKit/Source/modules/payments/PaymentRequestEvent.idl
diff --git a/third_party/WebKit/Source/modules/payments/PaymentRequestEvent.idl b/third_party/WebKit/Source/modules/payments/PaymentRequestEvent.idl
index 15e18ecca676dd712840250d0300de970396c624..0b9cffe9e4c158fabb82ce8679e54a0cf161cace 100644
--- a/third_party/WebKit/Source/modules/payments/PaymentRequestEvent.idl
+++ b/third_party/WebKit/Source/modules/payments/PaymentRequestEvent.idl
@@ -18,8 +18,6 @@
     readonly attribute sequence<PaymentDetailsModifier> modifiers;
     readonly attribute DOMString instrumentKey;
 
-    // TODO(gogerald): We should implement this function.
-    // Please see: http://crbug.com/720027
-    // Promise<WindowClient> openWindow(USVString url);
+    [CallWith=ScriptState] Promise<WindowClient?> openWindow(USVString url);

[zino, 2017/05/25 17:02:42]

This should be Promise<WindowClient> according to the spec.
Please see my another comment:
https://codereview.chromium.org/2893823004/patch/140001/150020

[please use gerrit instead, 2017/05/25 17:56:13]

What zino said.

[gogerald1, 2017/05/29 22:13:16]

Done.

     [CallWith=ScriptState, RaisesException] void respondWith(Promise<PaymentResponse> response);
 };