diff -r 000000000000 -r 6474c204b198 dom/webidl/NativeOSFileInternals.webidl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/webidl/NativeOSFileInternals.webidl	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 obtaone at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Options for nsINativeOSFileInternals::Read
+ */
+dictionary NativeOSFileReadOptions
+{
+  /**
+   * If specified, convert the raw bytes to a String
+   * with the specified encoding. Otherwise, return
+   * the raw bytes as a TypedArray.
+   */
+  DOMString? encoding;
+
+  /**
+   * If specified, limit the number of bytes to read.
+   */
+  unsigned long long? bytes;
+};