diff -r 000000000000 -r 6474c204b198 layout/xul/nsScrollBoxFrame.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/xul/nsScrollBoxFrame.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,176 @@
+/* -*- 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 "nsCOMPtr.h"
+#include "nsPresContext.h"
+#include "nsGkAtoms.h"
+#include "nsButtonBoxFrame.h"
+#include "nsITimer.h"
+#include "nsRepeatService.h"
+#include "mozilla/MouseEvents.h"
+#include "nsIContent.h"
+
+using namespace mozilla;
+
+class nsAutoRepeatBoxFrame : public nsButtonBoxFrame
+{
+public:
+  NS_DECL_FRAMEARENA_HELPERS
+
+  friend nsIFrame* NS_NewAutoRepeatBoxFrame(nsIPresShell* aPresShell,
+                                            nsStyleContext* aContext);
+
+  virtual void DestroyFrom(nsIFrame* aDestructRoot) MOZ_OVERRIDE;
+
+  virtual nsresult AttributeChanged(int32_t aNameSpaceID,
+                                    nsIAtom* aAttribute,
+                                    int32_t aModType) MOZ_OVERRIDE;
+
+  virtual nsresult HandleEvent(nsPresContext* aPresContext,
+                               WidgetGUIEvent* aEvent,
+                               nsEventStatus* aEventStatus) MOZ_OVERRIDE;
+
+  NS_IMETHOD HandlePress(nsPresContext* aPresContext,
+                         WidgetGUIEvent* aEvent,
+                         nsEventStatus* aEventStatus) MOZ_OVERRIDE;
+
+  NS_IMETHOD HandleRelease(nsPresContext* aPresContext,
+                           WidgetGUIEvent* aEvent,
+                           nsEventStatus* aEventStatus) MOZ_OVERRIDE;
+
+protected:
+  nsAutoRepeatBoxFrame(nsIPresShell* aPresShell, nsStyleContext* aContext):
+    nsButtonBoxFrame(aPresShell, aContext) {}
+  
+  void StartRepeat() {
+    if (IsActivatedOnHover()) {
+      // No initial delay on hover.
+      nsRepeatService::GetInstance()->Start(Notify, this, 0);
+    } else {
+      nsRepeatService::GetInstance()->Start(Notify, this);
+    }
+  }
+  void StopRepeat() {
+    nsRepeatService::GetInstance()->Stop(Notify, this);
+  }
+  void Notify();
+  static void Notify(void* aData) {
+    static_cast<nsAutoRepeatBoxFrame*>(aData)->Notify();
+  }
+
+  bool mTrustedEvent;
+  
+  bool IsActivatedOnHover();
+};
+
+nsIFrame*
+NS_NewAutoRepeatBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext)
+{
+  return new (aPresShell) nsAutoRepeatBoxFrame (aPresShell, aContext);
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsAutoRepeatBoxFrame)
+
+nsresult
+nsAutoRepeatBoxFrame::HandleEvent(nsPresContext* aPresContext,
+                                  WidgetGUIEvent* aEvent,
+                                  nsEventStatus* aEventStatus)
+{  
+  NS_ENSURE_ARG_POINTER(aEventStatus);
+  if (nsEventStatus_eConsumeNoDefault == *aEventStatus) {
+    return NS_OK;
+  }
+
+  switch(aEvent->message)
+  {
+    // repeat mode may be "hover" for repeating while the mouse is hovering
+    // over the element, otherwise repetition is done while the element is
+    // active (pressed).
+    case NS_MOUSE_ENTER:
+    case NS_MOUSE_ENTER_SYNTH:
+      if (IsActivatedOnHover()) {
+        StartRepeat();
+        mTrustedEvent = aEvent->mFlags.mIsTrusted;
+      }
+      break;
+
+    case NS_MOUSE_EXIT:
+    case NS_MOUSE_EXIT_SYNTH:
+      // always stop on mouse exit
+      StopRepeat();
+      // Not really necessary but do this to be safe
+      mTrustedEvent = false;
+      break;
+
+    case NS_MOUSE_CLICK: {
+      WidgetMouseEvent* mouseEvent = aEvent->AsMouseEvent();
+      if (mouseEvent->IsLeftClickEvent()) {
+        // skip button frame handling to prevent click handling
+        return nsBoxFrame::HandleEvent(aPresContext, mouseEvent, aEventStatus);
+      }
+      break;
+    }
+  }
+     
+  return nsButtonBoxFrame::HandleEvent(aPresContext, aEvent, aEventStatus);
+}
+
+NS_IMETHODIMP
+nsAutoRepeatBoxFrame::HandlePress(nsPresContext* aPresContext,
+                                  WidgetGUIEvent* aEvent,
+                                  nsEventStatus* aEventStatus)
+{
+  if (!IsActivatedOnHover()) {
+    StartRepeat();
+    mTrustedEvent = aEvent->mFlags.mIsTrusted;
+    DoMouseClick(aEvent, mTrustedEvent);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP 
+nsAutoRepeatBoxFrame::HandleRelease(nsPresContext* aPresContext,
+                                    WidgetGUIEvent* aEvent,
+                                    nsEventStatus* aEventStatus)
+{
+  if (!IsActivatedOnHover()) {
+    StopRepeat();
+  }
+  return NS_OK;
+}
+
+nsresult
+nsAutoRepeatBoxFrame::AttributeChanged(int32_t aNameSpaceID,
+                                       nsIAtom* aAttribute,
+                                       int32_t aModType)
+{
+  if (aAttribute == nsGkAtoms::type) {
+    StopRepeat();
+  }
+  return NS_OK;
+}
+
+void
+nsAutoRepeatBoxFrame::Notify()
+{
+  DoMouseClick(nullptr, mTrustedEvent);
+}
+
+void
+nsAutoRepeatBoxFrame::DestroyFrom(nsIFrame* aDestructRoot)
+{
+  // Ensure our repeat service isn't going... it's possible that a scrollbar can disappear out
+  // from under you while you're in the process of scrolling.
+  StopRepeat();
+  nsButtonBoxFrame::DestroyFrom(aDestructRoot);
+}
+
+bool
+nsAutoRepeatBoxFrame::IsActivatedOnHover()
+{
+  return mContent->AttrValueIs(kNameSpaceID_None, nsGkAtoms::repeat,
+                               nsGkAtoms::hover, eCaseMatters);
+}