--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -34,16 +34,17 @@
 #include "nsLayoutUtils.h"
 #include "nsBidiPresUtils.h"
 #include "nsBidiUtils.h"
 #include "mozilla/ContentEvents.h"
 #include "mozilla/EventDispatcher.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/LookAndFeel.h"
 #include "mozilla/dom/Element.h"
+#include "mozilla/dom/Event.h"
 #include "mozilla/dom/HTMLTextAreaElement.h"
 #include <stdint.h>
 #include "mozilla/MathAlgorithms.h"
 #include "mozilla/Telemetry.h"
 #include "FrameLayerBuilder.h"
 #include "nsSMILKeySpline.h"
 #include "nsSubDocumentFrame.h"
 #include "nsSVGOuterSVGFrame.h"
@@ -2180,16 +2181,17 @@ ScrollFrameHelper::CompleteAsyncScroll(c
   AutoWeakFrame weakFrame(mOuter);
   ScrollToImpl(mDestination, aRange, aOrigin);
   if (!weakFrame.IsAlive()) {
     return;
   }
   // We are done scrolling, set our destination to wherever we actually ended
   // up scrolling to.
   mDestination = GetScrollPosition();
+  FireScrollEndEvent();
 }
 
 bool
 ScrollFrameHelper::HasPluginFrames()
 {
 #if defined(XP_WIN) || defined(MOZ_WIDGET_GTK)
   if (XRE_IsContentProcess()) {
     nsPresContext* presContext = mOuter->PresContext();
@@ -4404,16 +4406,28 @@ ScrollFrameHelper::FireScrollPortEvent()
                                                       mVerticalOverflow) ?
     eScrollPortOverflow : eScrollPortUnderflow, nullptr);
   event.mOrient = orient;
   return EventDispatcher::Dispatch(mOuter->GetContent(),
                                    mOuter->PresContext(), &event);
 }
 
 void
+ScrollFrameHelper::FireScrollEndEvent()
+{
+  MOZ_ASSERT(mOuter->GetContent());
+  RefPtr<Event> event = NS_NewDOMEvent(mOuter->GetContent(), nullptr, nullptr);
+  event->InitEvent(NS_LITERAL_STRING("scrollend"), true, false);
+  event->SetTrusted(true);
+  event->WidgetEventPtr()->mFlags.mOnlyChromeDispatch = true;
+  bool dummy;
+  mOuter->GetContent()->DispatchEvent(event, &dummy);
+}
+
+void
 ScrollFrameHelper::ReloadChildFrames()
 {
   mScrolledFrame = nullptr;
   mHScrollbarBox = nullptr;
   mVScrollbarBox = nullptr;
   mScrollCornerBox = nullptr;
   mResizerBox = nullptr;
 

--- a/layout/generic/nsGfxScrollFrame.h
+++ b/layout/generic/nsGfxScrollFrame.h
@@ -64,16 +64,17 @@ public:
   // reload our child frame list.
   // We need this if a scrollbar frame is recreated.
   void ReloadChildFrames();
 
   nsresult CreateAnonymousContent(
     nsTArray<nsIAnonymousContentCreator::ContentInfo>& aElements);
   void AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements, uint32_t aFilter);
   nsresult FireScrollPortEvent();
+  void FireScrollEndEvent();
   void PostOverflowEvent();
   void Destroy();
 
   void BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                         const nsDisplayListSet& aLists);
 
   void AppendScrollPartsTo(nsDisplayListBuilder*   aBuilder,
                            const nsDisplayListSet& aLists,
@@ -394,16 +395,19 @@ public:
   bool ShouldClampScrollPosition() const;
 
   bool IsAlwaysActive() const;
   void MarkRecentlyScrolled();
   void MarkNotRecentlyScrolled();
   nsExpirationState* GetExpirationState() { return &mActivityExpirationState; }
 
   void SetTransformingByAPZ(bool aTransforming) {
+    if (mTransformingByAPZ && !aTransforming) {
+      FireScrollEndEvent();
+    }
     mTransformingByAPZ = aTransforming;
     if (!mozilla::css::TextOverflow::HasClippedOverflow(mOuter)) {
       // If the block has some text-overflow stuff we should kick off a paint
       // because we have special behaviour for it when APZ scrolling is active.
       mOuter->SchedulePaint();
     }
   }
   bool IsTransformingByAPZ() const {