Add FontFaceDescriptors IDL dictionary

Source/core/css/FontFaceDescriptors.idl

Index: Source/core/css/FontFaceDescriptors.idl
diff --git a/Source/core/css/FontFaceDescriptors.idl b/Source/core/css/FontFaceDescriptors.idl
new file mode 100644
index 0000000000000000000000000000000000000000..1ba9ef1cadccdd963d0415e3016bf1c4e12385c6
--- /dev/null
+++ b/Source/core/css/FontFaceDescriptors.idl
@@ -0,0 +1,14 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+[
+    GarbageCollected
+] dictionary FontFaceDescriptors {
+    DOMString style = "normal";
+    DOMString weight = "normal";
+    DOMString stretch = "normal";
+    DOMString unicodeRange = "U+0-10FFFF";
+    DOMString variant = "normal";
+    DOMString featureSettings = "normal";
+};