Roll 50: Copied IDLs, PYTHON scripts from WebKit removed deleted files in WebCore

modules/serviceworkers/FetchEvent.idl

Index: modules/serviceworkers/FetchEvent.idl
diff --git a/modules/serviceworkers/FetchEvent.idl b/modules/serviceworkers/FetchEvent.idl
index ffa53ecf83bf697f0b9258f83cf1afc0e0d488b4..e8f4551dcbe0d43b6f28ab6ecae7cd06f0253697 100644
--- a/modules/serviceworkers/FetchEvent.idl
+++ b/modules/serviceworkers/FetchEvent.idl
@@ -4,12 +4,12 @@
 
 // https://slightlyoff.github.io/ServiceWorker/spec/service_worker/index.html#fetch-event-interface
 [
-    Constructor(DOMString type, optional FetchEventInit eventInitDict),
+    Constructor(DOMString type, FetchEventInit eventInitDict),
     Exposed=ServiceWorker,
-    TypeChecking=Interface,
 ] interface FetchEvent : ExtendableEvent {
-    readonly attribute Request request;
+    [SameObject] readonly attribute Request request;
+    readonly attribute DOMString? clientId;
     readonly attribute boolean isReload;
 
-    [CallWith=ScriptState, RaisesException] void respondWith(any value);
+    [CallWith=ScriptState, RaisesException] void respondWith(Promise<Response> r);
 };