Implement MediaKeySession.generateRequest()

Source/modules/encryptedmedia/MediaKeys.idl

Index: Source/modules/encryptedmedia/MediaKeys.idl
diff --git a/Source/modules/encryptedmedia/MediaKeys.idl b/Source/modules/encryptedmedia/MediaKeys.idl
index 05dded46dae0f42b76153e5fd081176ceddaeb7c..14a542db449009f713c1fa3a3f33e09029ddd707 100644
--- a/Source/modules/encryptedmedia/MediaKeys.idl
+++ b/Source/modules/encryptedmedia/MediaKeys.idl
@@ -35,9 +35,9 @@ enum SessionType {
 ] interface MediaKeys {
     readonly attribute DOMString keySystem;
 
+    [CallWith=ScriptState] MediaKeySession createSession(optional SessionType sessionType = "temporary");
+
     [CallWith=ScriptState] static Promise create(DOMString keySystem);
-    [CallWith=ScriptState] Promise createSession(DOMString initDataType, ArrayBuffer initData, optional SessionType sessionType = "temporary");
-    [CallWith=ScriptState] Promise createSession(DOMString initDataType, ArrayBufferView initData, optional SessionType sessionType = "temporary");
 
     static boolean isTypeSupported(DOMString keySystem, optional DOMString contentType = null);
 };