ExtendableEvent and InstallEvent should have an EventConstructor

Source/modules/serviceworkers/ExtendableEvent.h

Index: Source/modules/serviceworkers/ExtendableEvent.h
diff --git a/Source/modules/serviceworkers/ExtendableEvent.h b/Source/modules/serviceworkers/ExtendableEvent.h
index 98282ccbaf61f51db56b38d62ffac07071963cb0..8ed7c8daaf368709d89e4481c4addc65da522186 100644
--- a/Source/modules/serviceworkers/ExtendableEvent.h
+++ b/Source/modules/serviceworkers/ExtendableEvent.h
@@ -38,11 +38,14 @@ namespace blink {
 
 class WaitUntilObserver;
 
+using ExtendableEventInit = EventInit;
+
 class ExtendableEvent : public Event {
     DEFINE_WRAPPERTYPEINFO();
 public:
     static PassRefPtrWillBeRawPtr<ExtendableEvent> create();
-    static PassRefPtrWillBeRawPtr<ExtendableEvent> create(const AtomicString& type, const EventInit&, WaitUntilObserver*);
+    static PassRefPtrWillBeRawPtr<ExtendableEvent> create(const AtomicString& type, const ExtendableEventInit&);
+    static PassRefPtrWillBeRawPtr<ExtendableEvent> create(const AtomicString& type, const ExtendableEventInit&, WaitUntilObserver*);
 
     virtual ~ExtendableEvent();
 
@@ -53,7 +56,8 @@ public:
 
 protected:
     ExtendableEvent();
-    ExtendableEvent(const AtomicString& type, const EventInit&, WaitUntilObserver*);
+    ExtendableEvent(const AtomicString& type, const ExtendableEventInit&);
+    ExtendableEvent(const AtomicString& type, const ExtendableEventInit&, WaitUntilObserver*);
 
     PersistentWillBeMember<WaitUntilObserver> m_observer;
 };