diff -r 000000000000 -r 6474c204b198 layout/base/ScrollbarStyles.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/base/ScrollbarStyles.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,31 @@
+/* -*- Mode: C++; 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/. */
+
+#ifndef ScrollbarStyles_h
+#define ScrollbarStyles_h
+
+#include <stdint.h>
+
+namespace mozilla {
+
+struct ScrollbarStyles
+{
+  // Always one of NS_STYLE_OVERFLOW_SCROLL, NS_STYLE_OVERFLOW_HIDDEN,
+  // or NS_STYLE_OVERFLOW_AUTO.
+  uint8_t mHorizontal;
+  uint8_t mVertical;
+  ScrollbarStyles(uint8_t h, uint8_t v) : mHorizontal(h), mVertical(v) {}
+  ScrollbarStyles() {}
+  bool operator==(const ScrollbarStyles& aStyles) const {
+    return aStyles.mHorizontal == mHorizontal && aStyles.mVertical == mVertical;
+  }
+  bool operator!=(const ScrollbarStyles& aStyles) const {
+    return aStyles.mHorizontal != mHorizontal || aStyles.mVertical != mVertical;
+  }
+};
+
+}
+
+#endif