Revert "Implementing window.createObjectURL*"

lib/dom/templates/html/dart2js/impl_Window.darttemplate

Index: lib/dom/templates/html/dart2js/impl_Window.darttemplate
diff --git a/lib/dom/templates/html/dart2js/impl_Window.darttemplate b/lib/dom/templates/html/dart2js/impl_Window.darttemplate
index f776d87ee5d4e6311955d89eee99d234e47e84bc..627f0b7b74baa056e906a6ff841ed2da121aa425 100644
--- a/lib/dom/templates/html/dart2js/impl_Window.darttemplate
+++ b/lib/dom/templates/html/dart2js/impl_Window.darttemplate
@@ -129,12 +129,5 @@ class $CLASSNAME$EXTENDS$IMPLEMENTS native "@*DOMWindow" {
     localStorage['dart-port:$name'] = JSON.stringify(serialized);
   }
 
-  String createObjectUrl(object) native '''
-    return (window.URL || window.webkitURL).createObjectURL(object)
-  ''';
-
-  void revokeObjectUrl(String objectUrl) native '''
-    (window.URL || window.webkitURL).revokeObjectURL(objectUrl)
-  ''';
 $!MEMBERS
 }