diff -r 000000000000 -r 6474c204b198 layout/xul/nsScrollbarFrame.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/xul/nsScrollbarFrame.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,90 @@
+/* -*- 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/. */
+
+//
+// nsScrollbarFrame
+//
+
+#ifndef nsScrollbarFrame_h__
+#define nsScrollbarFrame_h__
+
+#include "mozilla/Attributes.h"
+#include "nsBoxFrame.h"
+
+class nsIScrollbarMediator;
+
+nsIFrame* NS_NewScrollbarFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
+
+class nsScrollbarFrame : public nsBoxFrame
+{
+public:
+    nsScrollbarFrame(nsIPresShell* aShell, nsStyleContext* aContext):
+      nsBoxFrame(aShell, aContext), mScrollbarMediator(nullptr) {}
+
+  NS_DECL_QUERYFRAME_TARGET(nsScrollbarFrame)
+
+#ifdef DEBUG_FRAME_DUMP
+  virtual nsresult GetFrameName(nsAString& aResult) const MOZ_OVERRIDE {
+    return MakeFrameName(NS_LITERAL_STRING("ScrollbarFrame"), aResult);
+  }
+#endif
+
+  // nsIFrame overrides
+  virtual nsresult AttributeChanged(int32_t aNameSpaceID,
+                                    nsIAtom* aAttribute,
+                                    int32_t aModType) MOZ_OVERRIDE;
+
+  NS_DECL_QUERYFRAME
+  NS_DECL_FRAMEARENA_HELPERS
+
+  NS_IMETHOD HandlePress(nsPresContext* aPresContext,
+                         mozilla::WidgetGUIEvent* aEvent,
+                         nsEventStatus* aEventStatus) MOZ_OVERRIDE;
+
+  NS_IMETHOD HandleMultiplePress(nsPresContext* aPresContext,
+                                 mozilla::WidgetGUIEvent* aEvent,
+                                 nsEventStatus* aEventStatus,
+                                 bool aControlHeld) MOZ_OVERRIDE;
+
+  NS_IMETHOD HandleDrag(nsPresContext* aPresContext,
+                        mozilla::WidgetGUIEvent* aEvent,
+                        nsEventStatus* aEventStatus) MOZ_OVERRIDE;
+
+  NS_IMETHOD HandleRelease(nsPresContext* aPresContext,
+                           mozilla::WidgetGUIEvent* aEvent,
+                           nsEventStatus* aEventStatus) MOZ_OVERRIDE;
+
+  virtual void Init(nsIContent*      aContent,
+                    nsIFrame*        aParent,
+                    nsIFrame*        aPrevInFlow) MOZ_OVERRIDE;
+
+  virtual nsresult Reflow(nsPresContext*          aPresContext,
+                          nsHTMLReflowMetrics&     aDesiredSize,
+                          const nsHTMLReflowState& aReflowState,
+                          nsReflowStatus&          aStatus) MOZ_OVERRIDE;
+
+  virtual nsIAtom* GetType() const MOZ_OVERRIDE;  
+
+  void SetScrollbarMediatorContent(nsIContent* aMediator);
+  nsIScrollbarMediator* GetScrollbarMediator();
+
+  // nsBox methods
+
+  /**
+   * Treat scrollbars as clipping their children; overflowing children
+   * will not be allowed to set an overflow rect on this
+   * frame. This means that when the scroll code decides to hide a
+   * scrollframe by setting its height or width to zero, that will
+   * hide the children too.
+   */
+  virtual bool DoesClipChildren() MOZ_OVERRIDE { return true; }
+
+  virtual nsresult GetMargin(nsMargin& aMargin) MOZ_OVERRIDE;
+
+private:
+  nsCOMPtr<nsIContent> mScrollbarMediator;
+}; // class nsScrollbarFrame
+
+#endif