diff -r 000000000000 -r 6474c204b198 layout/xul/nsIScrollBoxObject.idl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/xul/nsIScrollBoxObject.idl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,52 @@
+/* -*- 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/. */
+
+#include "nsISupports.idl"
+
+interface nsIDOMElement;
+
+
+[scriptable, uuid(56E2ADA8-4631-11d4-BA11-001083023C1E)]
+interface nsIScrollBoxObject : nsISupports
+{
+  /**
+   * Scroll to the given coordinates, in css pixels.
+   * (0,0) will put the top left corner of the scrolled element's padding-box
+   * at the top left corner of the scrollport (which is its inner-border-box).
+   * Values will be clamped to legal values.
+   */
+  void scrollTo(in long x, in long y);
+
+  /**
+   * Scroll the given amount of device pixels to the right and down.
+   * Values will be clamped to make the resuling position legal.
+   */
+  void scrollBy(in long dx, in long dy);
+
+  void scrollByLine(in long dlines);
+  void scrollByIndex(in long dindexes);
+  void scrollToLine(in long line);
+  void scrollToElement(in nsIDOMElement child);
+  void scrollToIndex(in long index);
+
+  /**
+   * Get the current scroll position in css pixels.
+   * @see scrollTo for the definition of x and y.
+   */
+  void getPosition(out long x, out long y);
+
+  void getScrolledSize(out long width, out long height);
+  void ensureElementIsVisible(in nsIDOMElement child);
+  void ensureIndexIsVisible(in long index);
+  void ensureLineIsVisible(in long line);
+};
+
+%{C++
+class nsIBoxObject;
+
+nsresult
+NS_NewScrollBoxObject(nsIBoxObject** aResult);
+
+%}