diff --git a/gfx/layers/apz/src/APZUtils.cpp b/gfx/layers/apz/src/APZUtils.cpp
index 564160b47059..25cc1f536d82 100644
--- a/gfx/layers/apz/src/APZUtils.cpp
+++ b/gfx/layers/apz/src/APZUtils.cpp
@@ -40,6 +40,18 @@ CalculatePendingDisplayPort(const FrameMetrics& aFrameMetrics,
       aFrameMetrics, aVelocity);
 }
 
+/*static*/ bool
+IsCloseToHorizontal(float aAngle, float aThreshold)
+{
+  return (aAngle < aThreshold || aAngle > (M_PI - aThreshold));
+}
+
+/*static*/ bool
+IsCloseToVertical(float aAngle, float aThreshold)
+{
+  return (fabs(aAngle - (M_PI / 2)) < aThreshold);
+}
+
 } // namespace apz
 } // namespace layers
 } // namespace mozilla
diff --git a/gfx/layers/apz/src/APZUtils.h b/gfx/layers/apz/src/APZUtils.h
index bf5bf7ee26b0..0d07602dd6ff 100644
--- a/gfx/layers/apz/src/APZUtils.h
+++ b/gfx/layers/apz/src/APZUtils.h
@@ -131,6 +131,16 @@ void InitializeGlobalState();
 const ScreenMargin CalculatePendingDisplayPort(const FrameMetrics& aFrameMetrics,
                                                const ParentLayerPoint& aVelocity);
 
+/**
+ * Is aAngle within the given threshold of the horizontal axis?
+ * @param aAngle an angle in radians in the range [0, pi]
+ * @param aThreshold an angle in radians in the range [0, pi/2]
+ */
+bool IsCloseToHorizontal(float aAngle, float aThreshold);
+
+// As above, but for the vertical axis.
+bool IsCloseToVertical(float aAngle, float aThreshold);
+
 } // namespace apz
 
 } // namespace layers
diff --git a/gfx/layers/apz/src/AsyncPanZoomController.cpp b/gfx/layers/apz/src/AsyncPanZoomController.cpp
index 8d28ebb377c1..4afd1b4c0dd7 100644
--- a/gfx/layers/apz/src/AsyncPanZoomController.cpp
+++ b/gfx/layers/apz/src/AsyncPanZoomController.cpp
@@ -524,22 +524,6 @@ static bool IsHighMemSystem()
   return gIsHighMemSystem;
 }
 
-/**
- * Is aAngle within the given threshold of the horizontal axis?
- * @param aAngle an angle in radians in the range [0, pi]
- * @param aThreshold an angle in radians in the range [0, pi/2]
- */
-static bool IsCloseToHorizontal(float aAngle, float aThreshold)
-{
-  return (aAngle < aThreshold || aAngle > (M_PI - aThreshold));
-}
-
-// As above, but for the vertical axis.
-static bool IsCloseToVertical(float aAngle, float aThreshold)
-{
-  return (fabs(aAngle - (M_PI / 2)) < aThreshold);
-}
-
 // Counter used to give each APZC a unique id
 static uint32_t sAsyncPanZoomControllerCount = 0;
 
@@ -2765,10 +2749,10 @@ void AsyncPanZoomController::HandlePanningWithTouchAction(double aAngle) {
     overscrollHandoffChain->CanScrollInDirection(this, ScrollDirection::eVertical);
   if (GetCurrentTouchBlock()->TouchActionAllowsPanningXY()) {
     if (canScrollHorizontal && canScrollVertical) {
-      if (IsCloseToHorizontal(aAngle, gfxPrefs::APZAxisLockAngle())) {
+      if (apz::IsCloseToHorizontal(aAngle, gfxPrefs::APZAxisLockAngle())) {
         mY.SetAxisLocked(true);
         SetState(PANNING_LOCKED_X);
-      } else if (IsCloseToVertical(aAngle, gfxPrefs::APZAxisLockAngle())) {
+      } else if (apz::IsCloseToVertical(aAngle, gfxPrefs::APZAxisLockAngle())) {
         mX.SetAxisLocked(true);
         SetState(PANNING_LOCKED_Y);
       } else {
@@ -2782,7 +2766,7 @@ void AsyncPanZoomController::HandlePanningWithTouchAction(double aAngle) {
   } else if (GetCurrentTouchBlock()->TouchActionAllowsPanningX()) {
     // Using bigger angle for panning to keep behavior consistent
     // with IE.
-    if (IsCloseToHorizontal(aAngle, gfxPrefs::APZAllowedDirectPanAngle())) {
+    if (apz::IsCloseToHorizontal(aAngle, gfxPrefs::APZAllowedDirectPanAngle())) {
       mY.SetAxisLocked(true);
       SetState(PANNING_LOCKED_X);
       mPanDirRestricted = true;
@@ -2792,7 +2776,7 @@ void AsyncPanZoomController::HandlePanningWithTouchAction(double aAngle) {
       SetState(NOTHING);
     }
   } else if (GetCurrentTouchBlock()->TouchActionAllowsPanningY()) {
-    if (IsCloseToVertical(aAngle, gfxPrefs::APZAllowedDirectPanAngle())) {
+    if (apz::IsCloseToVertical(aAngle, gfxPrefs::APZAllowedDirectPanAngle())) {
       mX.SetAxisLocked(true);
       SetState(PANNING_LOCKED_Y);
       mPanDirRestricted = true;
@@ -2823,12 +2807,12 @@ void AsyncPanZoomController::HandlePanning(double aAngle) {
 
   if (!canScrollHorizontal || !canScrollVertical) {
     SetState(PANNING);
-  } else if (IsCloseToHorizontal(aAngle, gfxPrefs::APZAxisLockAngle())) {
+  } else if (apz::IsCloseToHorizontal(aAngle, gfxPrefs::APZAxisLockAngle())) {
     mY.SetAxisLocked(true);
     if (canScrollHorizontal) {
       SetState(PANNING_LOCKED_X);
     }
-  } else if (IsCloseToVertical(aAngle, gfxPrefs::APZAxisLockAngle())) {
+  } else if (apz::IsCloseToVertical(aAngle, gfxPrefs::APZAxisLockAngle())) {
     mX.SetAxisLocked(true);
     if (canScrollVertical) {
       SetState(PANNING_LOCKED_Y);
@@ -2849,12 +2833,12 @@ void AsyncPanZoomController::HandlePanningUpdate(const ScreenPoint& aPanDistance
 
     if (fabs(aPanDistance.x) > breakThreshold || fabs(aPanDistance.y) > breakThreshold) {
       if (mState == PANNING_LOCKED_X) {
-        if (!IsCloseToHorizontal(angle, gfxPrefs::APZAxisBreakoutAngle())) {
+        if (!apz::IsCloseToHorizontal(angle, gfxPrefs::APZAxisBreakoutAngle())) {
           mY.SetAxisLocked(false);
           SetState(PANNING);
         }
       } else if (mState == PANNING_LOCKED_Y) {
-        if (!IsCloseToVertical(angle, gfxPrefs::APZAxisBreakoutAngle())) {
+        if (!apz::IsCloseToVertical(angle, gfxPrefs::APZAxisBreakoutAngle())) {
           mX.SetAxisLocked(false);
           SetState(PANNING);
         }