Service Worker: Correct Web IDL of ExtendableEvent.waitUntil method.

Source/modules/serviceworkers/ExtendableEvent.idl

Index: Source/modules/serviceworkers/ExtendableEvent.idl
diff --git a/Source/modules/serviceworkers/ExtendableEvent.idl b/Source/modules/serviceworkers/ExtendableEvent.idl
index df1bc885b9cf090440d1c0addeae378f30c38955..a3b5686b06b348847860d7bcc894807c9608b48a 100644
--- a/Source/modules/serviceworkers/ExtendableEvent.idl
+++ b/Source/modules/serviceworkers/ExtendableEvent.idl
@@ -34,5 +34,5 @@
     Exposed=ServiceWorker,
     TypeChecking=Interface,
 ] interface ExtendableEvent : Event {
-    [CallWith=ScriptState, RaisesException] void waitUntil(any value);
+    [CallWith=ScriptState, RaisesException] void waitUntil(Promise<any> f);

[falken, 2015/07/29 08:14:55]

what does f stand for? I see it's in the spec as well. Should it be something
more understandable or is this a common convention?

[jungkees, 2015/07/29 08:34:18]

Ah, I didn't see this comment before seeing an lgtm from nhiroki and committing
it.

I also had a same question. I don't think it is a convention, but couldn't come
up with a better generic name that represents just a *functional entity* that
can be either a promise or a value there.

I guess Jake or Alex initially named it so. I'm willing to change it if we have
a better one for it.

 };