--- a/gfx/layers/apz/src/AsyncPanZoomController.cpp
+++ b/gfx/layers/apz/src/AsyncPanZoomController.cpp
@@ -3924,16 +3924,21 @@ void AsyncPanZoomController::NotifyLayer
   UpdateSharedCompositorFrameMetrics();
 }
 
 const FrameMetrics& AsyncPanZoomController::GetFrameMetrics() const {
   mRecursiveMutex.AssertCurrentThreadIn();
   return mFrameMetrics;
 }
 
+const ScrollMetadata& AsyncPanZoomController::GetScrollMetadata() const {
+  mRecursiveMutex.AssertCurrentThreadIn();
+  return mScrollMetadata;
+}
+
 APZCTreeManager* AsyncPanZoomController::GetApzcTreeManager() const {
   mRecursiveMutex.AssertNotCurrentThreadIn();
   return mTreeManager;
 }
 
 void AsyncPanZoomController::ZoomToRect(CSSRect aRect, const uint32_t aFlags) {
   if (!aRect.IsFinite()) {
     NS_WARNING("ZoomToRect got called with a non-finite rect; ignoring...");

--- a/gfx/layers/apz/src/AsyncPanZoomController.h
+++ b/gfx/layers/apz/src/AsyncPanZoomController.h
@@ -664,16 +664,22 @@ protected:
 
   /**
    * Gets the current frame metrics. This is *not* the Gecko copy stored in the
    * layers code.
    */
   const FrameMetrics& GetFrameMetrics() const;
 
   /**
+   * Gets the current scroll metadata. This is *not* the Gecko copy stored in
+   * the layers code/
+   */
+  const ScrollMetadata& GetScrollMetadata() const;
+
+  /**
    * Gets the pointer to the apzc tree manager. All the access to tree manager
    * should be made via this method and not via private variable since this method
    * ensures that no lock is set.
    */
   APZCTreeManager* GetApzcTreeManager() const;
 
   /**
    * Convert ScreenPoint relative to the screen to LayoutDevicePoint relative

--- a/gfx/layers/apz/src/Axis.cpp
+++ b/gfx/layers/apz/src/Axis.cpp
@@ -486,16 +486,31 @@ bool Axis::ScaleWillOverscrollBothSides(
                                           / ParentLayerToParentLayerScale(aScale);
   return GetRectLength(screenCompositionBounds) - GetPageLength() > COORDINATE_EPSILON;
 }
 
 const FrameMetrics& Axis::GetFrameMetrics() const {
   return mAsyncPanZoomController->GetFrameMetrics();
 }
 
+const ScrollMetadata& Axis::GetScrollMetadata() const {
+  return mAsyncPanZoomController->GetScrollMetadata();
+}
+
+bool Axis::OverscrollBehaviorAllowsHandoff() const {
+  // Scroll handoff is a "non-local" overscroll behavior, so it's allowed
+  // with "auto" and disallowed with "contain" and "none".
+  return GetOverscrollBehavior() == OverscrollBehavior::Auto;
+}
+
+bool Axis::OverscrollBehaviorAllowsOverscrollEffect() const {
+  // An overscroll effect is a "local" overscroll behavior, so it's allowed
+  // with "auto" and "contain" and disallowed with "none".
+  return GetOverscrollBehavior() != OverscrollBehavior::None;
+}
 
 AxisX::AxisX(AsyncPanZoomController* aAsyncPanZoomController)
   : Axis(aAsyncPanZoomController)
 {
 
 }
 
 ParentLayerCoord AxisX::GetPointOffset(const ParentLayerPoint& aPoint) const
@@ -523,16 +538,21 @@ ScreenPoint AxisX::MakePoint(ScreenCoord
   return ScreenPoint(aCoord, 0);
 }
 
 const char* AxisX::Name() const
 {
   return "X";
 }
 
+OverscrollBehavior AxisX::GetOverscrollBehavior() const
+{
+  return GetScrollMetadata().GetOverscrollBehavior().mBehaviorX;
+}
+
 AxisY::AxisY(AsyncPanZoomController* aAsyncPanZoomController)
   : Axis(aAsyncPanZoomController)
 {
 
 }
 
 ParentLayerCoord AxisY::GetPointOffset(const ParentLayerPoint& aPoint) const
 {
@@ -559,10 +579,15 @@ ScreenPoint AxisY::MakePoint(ScreenCoord
   return ScreenPoint(0, aCoord);
 }
 
 const char* AxisY::Name() const
 {
   return "Y";
 }
 
+OverscrollBehavior AxisY::GetOverscrollBehavior() const
+{
+  return GetScrollMetadata().GetOverscrollBehavior().mBehaviorY;
+}
+
 } // namespace layers
 } // namespace mozilla

--- a/gfx/layers/apz/src/Axis.h
+++ b/gfx/layers/apz/src/Axis.h
@@ -244,16 +244,19 @@ public:
   ParentLayerCoord GetPageStart() const;
   ParentLayerCoord GetPageLength() const;
   ParentLayerCoord GetCompositionEnd() const;
   ParentLayerCoord GetPageEnd() const;
   ParentLayerCoord GetScrollRangeEnd() const;
 
   ParentLayerCoord GetPos() const { return mPos; }
 
+  bool OverscrollBehaviorAllowsHandoff() const;
+  bool OverscrollBehaviorAllowsOverscrollEffect() const;
+
   virtual ParentLayerCoord GetPointOffset(const ParentLayerPoint& aPoint) const = 0;
   virtual ParentLayerCoord GetRectLength(const ParentLayerRect& aRect) const = 0;
   virtual ParentLayerCoord GetRectOffset(const ParentLayerRect& aRect) const = 0;
   virtual CSSToParentLayerScale GetScaleForAxis(const CSSToParentLayerScale2D& aScale) const = 0;
 
   virtual ScreenPoint MakePoint(ScreenCoord aCoord) const = 0;
 
   virtual const char* Name() const = 0;
@@ -281,16 +284,19 @@ protected:
 
   // A queue of (timestamp, velocity) pairs; these are the historical
   // velocities at the given timestamps. Timestamps are in milliseconds,
   // velocities are in screen pixels per ms. This member can only be
   // accessed on the controller/UI thread.
   nsTArray<std::pair<uint32_t, float> > mVelocityQueue;
 
   const FrameMetrics& GetFrameMetrics() const;
+  const ScrollMetadata& GetScrollMetadata() const;
+
+  virtual OverscrollBehavior GetOverscrollBehavior() const = 0;
 
   // Adjust a requested overscroll amount for resistance, yielding a smaller
   // actual overscroll amount.
   ParentLayerCoord ApplyResistance(ParentLayerCoord aOverscroll) const;
 
   // Helper function for SampleOverscrollAnimation().
   void StepOverscrollAnimation(double aStepDurationMilliseconds);
 
@@ -302,25 +308,29 @@ class AxisX : public Axis {
 public:
   explicit AxisX(AsyncPanZoomController* mAsyncPanZoomController);
   virtual ParentLayerCoord GetPointOffset(const ParentLayerPoint& aPoint) const override;
   virtual ParentLayerCoord GetRectLength(const ParentLayerRect& aRect) const override;
   virtual ParentLayerCoord GetRectOffset(const ParentLayerRect& aRect) const override;
   virtual CSSToParentLayerScale GetScaleForAxis(const CSSToParentLayerScale2D& aScale) const override;
   virtual ScreenPoint MakePoint(ScreenCoord aCoord) const override;
   virtual const char* Name() const override;
+private:
+  virtual OverscrollBehavior GetOverscrollBehavior() const override;
 };
 
 class AxisY : public Axis {
 public:
   explicit AxisY(AsyncPanZoomController* mAsyncPanZoomController);
   virtual ParentLayerCoord GetPointOffset(const ParentLayerPoint& aPoint) const override;
   virtual ParentLayerCoord GetRectLength(const ParentLayerRect& aRect) const override;
   virtual ParentLayerCoord GetRectOffset(const ParentLayerRect& aRect) const override;
   virtual CSSToParentLayerScale GetScaleForAxis(const CSSToParentLayerScale2D& aScale) const override;
   virtual ScreenPoint MakePoint(ScreenCoord aCoord) const override;
   virtual const char* Name() const override;
+private:
+  virtual OverscrollBehavior GetOverscrollBehavior() const override;
 };
 
 } // namespace layers
 } // namespace mozilla
 
 #endif