[Payments] Implement openWindow for service worker based payment handler

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PaymentRequestEvent_h
 #define PaymentRequestEvent_h
 
 #include "modules/EventModules.h"
 #include "modules/payments/PaymentAppRequest.h"
 #include "modules/serviceworkers/ExtendableEvent.h"
@@ skipping 21 matching lines @@
   const AtomicString& InterfaceName() const override;
 
   const String& topLevelOrigin() const;
   const String& paymentRequestOrigin() const;
   const String& paymentRequestId() const;
   const HeapVector<PaymentMethodData>& methodData() const;
   void total(PaymentItem& value) const;
   const HeapVector<PaymentDetailsModifier>& modifiers() const;
   const String& instrumentKey() const;
 
+  ScriptPromise openWindow(ScriptState*, const String& url);
   void respondWith(ScriptState*, ScriptPromise, ExceptionState&);
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
   PaymentRequestEvent(const AtomicString& type,
                       const PaymentAppRequest&,
                       RespondWithObserver*,
                       WaitUntilObserver*);
 
   String top_level_origin_;
   String payment_request_origin_;
   String payment_request_id_;
   HeapVector<PaymentMethodData> method_data_;
   PaymentItem total_;
   HeapVector<PaymentDetailsModifier> modifiers_;
   String instrument_key_;
 
   Member<RespondWithObserver> observer_;
 };
 
 }  // namespace blink
 
 #endif  // PaymentRequestEvent_h