diff -r 000000000000 -r 6474c204b198 dom/interfaces/canvas/nsIDOMWebGLRenderingContext.idl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/interfaces/canvas/nsIDOMWebGLRenderingContext.idl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,15 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 "nsISupports.idl"
+
+[builtinclass, uuid(f1a2fd3a-c6ac-4ee2-a700-5d285d5e3fff)]
+interface nsIDOMWebGLRenderingContext : nsISupports
+{
+  // get an underlying GL parameter, without any WebGL intervention.
+  // Most useful for querying GL_VENDOR/GL_RENDERER for identifying
+  // the underlying renderer to the user.
+  [noscript] DOMString mozGetUnderlyingParamString(in unsigned long pname);
+};