Introduce XMLHttpRequestEventTarget IDL interface

Source/core/xml/XMLHttpRequestEventTarget.idl

Index: Source/core/xml/XMLHttpRequestEventTarget.idl
diff --git a/Source/core/page/WindowBase64.idl b/Source/core/xml/XMLHttpRequestEventTarget.idl
similarity index 77%
copy from Source/core/page/WindowBase64.idl
copy to Source/core/xml/XMLHttpRequestEventTarget.idl
index e27a93b90ee5e16638b0b1a3367cbcb9ff000dfe..7ec93d9c456592106aaca2adfe29e8bdb4fe0cff 100644
--- a/Source/core/page/WindowBase64.idl
+++ b/Source/core/xml/XMLHttpRequestEventTarget.idl
@@ -1,6 +1,5 @@
 /*
- * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
- * Copyright (C) 2011 Google Inc. All rights reserved.
+ * Copyright (C) 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Samsung Electronics. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -26,9 +25,13 @@
  */
 
 [
-    NoInterfaceObject,
-    ImplementedAs=DOMWindowBase64
-] interface WindowBase64 {
-    [RaisesException] DOMString atob(DOMString string);
-    [RaisesException] DOMString btoa(DOMString string);
+    NoInterfaceObject
+] interface XMLHttpRequestEventTarget : EventTarget {
+    attribute EventHandler onabort;
+    attribute EventHandler onerror;
+    attribute EventHandler onload;
+    attribute EventHandler onloadend;
+    attribute EventHandler onloadstart;
+    attribute EventHandler onprogress;
+    attribute EventHandler ontimeout;
 };