Warn web developer on missing favicon for PaymentRequest UI.

third_party/WebKit/Source/modules/payments/PaymentRequest.cpp

Index: third_party/WebKit/Source/modules/payments/PaymentRequest.cpp
diff --git a/third_party/WebKit/Source/modules/payments/PaymentRequest.cpp b/third_party/WebKit/Source/modules/payments/PaymentRequest.cpp
index 9759e63f2eccaaa13af83dcfd05b94e0cb542119..a8ae62c0978d10cd54e07a3508863b6ccbbe186a 100644
--- a/third_party/WebKit/Source/modules/payments/PaymentRequest.cpp
+++ b/third_party/WebKit/Source/modules/payments/PaymentRequest.cpp
@@ -1056,6 +1056,13 @@ void PaymentRequest::OnCanMakePayment(CanMakePaymentQueryResult result) {
   can_make_payment_resolver_.Clear();
 }
 
+void PaymentRequest::WarnNoFavicon() {
+  GetExecutionContext()->AddConsoleMessage(
+      ConsoleMessage::Create(kJSMessageSource, kWarningMessageLevel,
+                             "Favicon not found for PaymentRequest UI. User "
+                             "may not recognize the website."));
+}
+
 void PaymentRequest::OnCompleteTimeout(TimerBase*) {
   GetExecutionContext()->AddConsoleMessage(ConsoleMessage::Create(
       kJSMessageSource, kErrorMessageLevel,