diff --git a/widget/InputData.cpp b/widget/InputData.cpp
index c0dbce823a5..df64b05af78 100644
--- a/widget/InputData.cpp
+++ b/widget/InputData.cpp
@@ -225,6 +225,40 @@ MultiTouchInput::TransformToLocal(const gfx::Matrix4x4& aTransform)
   return true;
 }
 
+bool
+PanGestureInput::IsMomentum() const
+{
+  switch (mType) {
+    case PanGestureInput::PANGESTURE_MOMENTUMSTART:
+    case PanGestureInput::PANGESTURE_MOMENTUMPAN:
+    case PanGestureInput::PANGESTURE_MOMENTUMEND:
+      return true;
+    default:
+      return false;
+  }
+}
+
+WidgetWheelEvent
+PanGestureInput::ToWidgetWheelEvent(nsIWidget* aWidget) const
+{
+  WidgetWheelEvent wheelEvent(true, NS_WHEEL_WHEEL, aWidget);
+  wheelEvent.modifiers = this->modifiers;
+  wheelEvent.time = mTime;
+  wheelEvent.timeStamp = mTimeStamp;
+  wheelEvent.refPoint =
+    RoundedToInt(ViewAs<LayoutDevicePixel>(mPanStartPoint,
+      PixelCastJustification::LayoutDeviceToScreenForUntransformedEvent));
+  wheelEvent.buttons = 0;
+  wheelEvent.deltaMode = nsIDOMWheelEvent::DOM_DELTA_PIXEL;
+  wheelEvent.isMomentum = IsMomentum();
+  wheelEvent.lineOrPageDeltaX = mLineOrPageDeltaX;
+  wheelEvent.lineOrPageDeltaY = mLineOrPageDeltaY;
+  wheelEvent.deltaX = mPanDisplacement.x;
+  wheelEvent.deltaY = mPanDisplacement.y;
+  wheelEvent.mFlags.mHandledByAPZ = true;
+  return wheelEvent;
+}
+
 bool
 PanGestureInput::TransformToLocal(const gfx::Matrix4x4& aTransform)
 { 
@@ -264,6 +298,39 @@ TapGestureInput::TransformToLocal(const gfx::Matrix4x4& aTransform)
   return true;
 }
 
+static uint32_t
+DeltaModeForDeltaType(ScrollWheelInput::ScrollDeltaType aDeltaType)
+{
+  switch (aDeltaType) {
+    case ScrollWheelInput::SCROLLDELTA_LINE:
+      return nsIDOMWheelEvent::DOM_DELTA_LINE;
+    case ScrollWheelInput::SCROLLDELTA_PIXEL:
+    default:
+      return nsIDOMWheelEvent::DOM_DELTA_PIXEL;
+  }
+}
+
+WidgetWheelEvent
+ScrollWheelInput::ToWidgetWheelEvent(nsIWidget* aWidget) const
+{
+  WidgetWheelEvent wheelEvent(true, NS_WHEEL_WHEEL, aWidget);
+  wheelEvent.modifiers = this->modifiers;
+  wheelEvent.time = mTime;
+  wheelEvent.timeStamp = mTimeStamp;
+  wheelEvent.refPoint =
+    RoundedToInt(ViewAs<LayoutDevicePixel>(mOrigin,
+      PixelCastJustification::LayoutDeviceToScreenForUntransformedEvent));
+  wheelEvent.buttons = 0;
+  wheelEvent.deltaMode = DeltaModeForDeltaType(mDeltaType);
+  wheelEvent.isMomentum = mIsMomentum;
+  wheelEvent.deltaX = mDeltaX;
+  wheelEvent.deltaY = mDeltaY;
+  wheelEvent.lineOrPageDeltaX = mLineOrPageDeltaX;
+  wheelEvent.lineOrPageDeltaY = mLineOrPageDeltaY;
+  wheelEvent.mFlags.mHandledByAPZ = true;
+  return wheelEvent;
+}
+
 bool
 ScrollWheelInput::TransformToLocal(const gfx::Matrix4x4& aTransform)
 {
diff --git a/widget/InputData.h b/widget/InputData.h
index 48a90f329d2..112c66d9fe0 100644
--- a/widget/InputData.h
+++ b/widget/InputData.h
@@ -307,10 +307,16 @@ public:
     : InputData(PANGESTURE_INPUT, aTime, aTimeStamp, aModifiers),
       mType(aType),
       mPanStartPoint(aPanStartPoint),
-      mPanDisplacement(aPanDisplacement)
+      mPanDisplacement(aPanDisplacement),
+      mLineOrPageDeltaX(0),
+      mLineOrPageDeltaY(0)
   {
   }
 
+  bool IsMomentum() const;
+
+  WidgetWheelEvent ToWidgetWheelEvent(nsIWidget* aWidget) const;
+
   bool TransformToLocal(const gfx::Matrix4x4& aTransform);
 
   PanGestureType mType;
@@ -323,6 +329,10 @@ public:
   // coordinates of the APZC receiving the pan. These are set and used by APZ.
   ParentLayerPoint mLocalPanStartPoint;
   ParentLayerPoint mLocalPanDisplacement;
+
+  // See lineOrPageDeltaX/Y on WidgetWheelEvent.
+  int32_t mLineOrPageDeltaX;
+  int32_t mLineOrPageDeltaY;
 };
 
 /**
@@ -503,9 +513,13 @@ public:
      mScrollMode(aScrollMode),
      mOrigin(aOrigin),
      mDeltaX(aDeltaX),
-     mDeltaY(aDeltaY)
+     mDeltaY(aDeltaY),
+     mLineOrPageDeltaX(0),
+     mLineOrPageDeltaY(0),
+     mIsMomentum(false)
   {}
 
+  WidgetWheelEvent ToWidgetWheelEvent(nsIWidget* aWidget) const;
   bool TransformToLocal(const gfx::Matrix4x4& aTransform);
 
   ScrollDeltaType mDeltaType;
@@ -525,6 +539,12 @@ public:
   // The location of the scroll in local coordinates. This is set and used by
   // APZ.
   ParentLayerPoint mLocalOrigin;
+
+  // See lineOrPageDeltaX/Y on WidgetWheelEvent.
+  int32_t mLineOrPageDeltaX;
+  int32_t mLineOrPageDeltaY;
+
+  bool mIsMomentum;
 };
 
 } // namespace mozilla