[Payments] Introduce basic interactive browsertests for Payment Request

components/payments/payment_request_web_contents_manager.cc

Index: components/payments/payment_request_web_contents_manager.cc
diff --git a/components/payments/payment_request_web_contents_manager.cc b/components/payments/payment_request_web_contents_manager.cc
index bb358f921345e494a0a520db3d5aa9619a545a45..ca893723f6fd8a1491cd5e13f7324369ff585fef 100644
--- a/components/payments/payment_request_web_contents_manager.cc
+++ b/components/payments/payment_request_web_contents_manager.cc
@@ -20,7 +20,7 @@ PaymentRequestWebContentsManager*
 PaymentRequestWebContentsManager::GetOrCreateForWebContents(
     content::WebContents* web_contents) {
   DCHECK(web_contents);
-  // CreateForWebContents does nothing if the delegate instance already exists.
+  // CreateForWebContents does nothing if the manager instance already exists.
   PaymentRequestWebContentsManager::CreateForWebContents(web_contents);
   return PaymentRequestWebContentsManager::FromWebContents(web_contents);
 }