iframes with allowpaymentrequest attribute are allowed to make payment requests.

third_party/WebKit/Source/web/FrameLoaderClientImpl.cpp

Index: third_party/WebKit/Source/web/FrameLoaderClientImpl.cpp
diff --git a/third_party/WebKit/Source/web/FrameLoaderClientImpl.cpp b/third_party/WebKit/Source/web/FrameLoaderClientImpl.cpp
index db1de678cac7e8bda77e43567030f9960c02da88..72429d7fcb3e290d39b5466e58d437b7a25e7042 100644
--- a/third_party/WebKit/Source/web/FrameLoaderClientImpl.cpp
+++ b/third_party/WebKit/Source/web/FrameLoaderClientImpl.cpp
@@ -894,7 +894,8 @@ void FrameLoaderClientImpl::didChangeFrameOwnerProperties(
       WebFrameOwnerProperties(
           frameElement->scrollingMode(), frameElement->marginWidth(),
           frameElement->marginHeight(), frameElement->allowFullscreen(),
-          frameElement->csp(), frameElement->delegatedPermissions()));
+          frameElement->allowPaymentRequest(), frameElement->csp(),

[pals, 2016/10/19 12:53:12]

HTMLIFrameElement needs to override allowPaymentRequest()as it is being used
here. 

[haraken, 2016/10/19 15:37:56]

Can we avoid the override by changing the line to something liek:

  HTMLIFrameElementPayments::from(frameElement)->allowPaymentRequest()

?

[pals, 2016/10/20 09:30:07]

Done. 

+          frameElement->delegatedPermissions()));
 }
 
 void FrameLoaderClientImpl::dispatchWillStartUsingPeerConnectionHandler(