diff -r 000000000000 -r 6474c204b198 dom/ipc/PFileDescriptorSet.ipdl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/ipc/PFileDescriptorSet.ipdl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,21 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PContent;
+
+namespace mozilla {
+namespace dom {
+
+protocol PFileDescriptorSet
+{
+  manager PContent;
+
+both:
+  AddFileDescriptor(FileDescriptor fd);
+
+  __delete__();
+};
+
+} // namespace dom
+} // namespace mozilla