diff -r 000000000000 -r 6474c204b198 dom/plugins/ipc/AStream.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/plugins/ipc/AStream.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,27 @@
+/* -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 8 -*- */
+/* 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/. */
+
+#ifndef mozilla_plugins_AStream_h
+#define mozilla_plugins_AStream_h
+
+namespace mozilla {
+namespace plugins {
+
+/**
+ * When we are passed NPStream->{ndata,pdata} in {NPN,NPP}_DestroyStream, we
+ * don't know whether it's a plugin stream or a browser stream. This abstract
+ * class lets us cast to the right type of object and send the appropriate
+ * message.
+ */
+class AStream
+{
+public:
+  virtual bool IsBrowserStream() = 0;
+};
+
+} // namespace plugins
+} // namespace mozilla
+
+#endif