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diff --git a/gfx/layers/apz/public/APZPublicUtils.h b/gfx/layers/apz/public/APZPublicUtils.h
new file mode 100644
index 0000000000..6433008b4c
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+++ b/gfx/layers/apz/public/APZPublicUtils.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#ifndef mozilla_layers_APZPublicUtils_h
+#define mozilla_layers_APZPublicUtils_h
+
+// This file is for APZ-related utilities that need to be consumed from outside
+// of gfx/layers. For internal utilities, prefer APZUtils.h.
+
+#include <stdint.h>
+#include <utility>
+#include "ScrollAnimationBezierPhysics.h"
+#include "Units.h"
+#include "mozilla/DefineEnum.h"
+#include "mozilla/ScrollOrigin.h"
+#include "mozilla/gfx/Point.h"
+#include "mozilla/ScrollTypes.h"
+
+namespace mozilla {
+
+namespace layers {
+
+struct FrameMetrics;
+
+// clang-format off
+MOZ_DEFINE_ENUM_CLASS_WITH_BASE(APZWheelAction, uint8_t, (
+    Scroll,
+    PinchZoom
+))
+// clang-format on
+
+namespace apz {
+
+/**
+ * Initializes the global state used in AsyncPanZoomController.
+ * This is normally called when it is first needed in the constructor
+ * of APZCTreeManager, but can be called manually to force it to be
+ * initialized earlier.
+ */
+void InitializeGlobalState();
+
+/**
+ * See AsyncPanZoomController::CalculatePendingDisplayPort. This
+ * function simply delegates to that one, so that non-layers code
+ * never needs to include AsyncPanZoomController.h
+ */
+const ScreenMargin CalculatePendingDisplayPort(
+    const FrameMetrics& aFrameMetrics, const ParentLayerPoint& aVelocity);
+
+/**
+ * Returns a width and height multiplier, each of which is a power of two
+ * between 1 and 8 inclusive. The multiplier is chosen based on the provided
+ * base size, such that multiplier is larger when the base size is larger.
+ * The exact details are somewhat arbitrary and tuned by hand.
+ * This function is intended to only be used with WebRender, because that is
+ * the codepath that wants to use a larger displayport alignment, because
+ * moving the displayport is relatively expensive with WebRender.
+ */
+gfx::IntSize GetDisplayportAlignmentMultiplier(const ScreenSize& aBaseSize);
+
+/**
+ * Calculate the physics parameters for smooth scroll animations for the
+ * given origin, based on pref values.
+ */
+ScrollAnimationBezierPhysicsSettings ComputeBezierAnimationSettingsForOrigin(
+    ScrollOrigin aOrigin);
+
+/**
+ * Calculate if the scrolling should be instant or smooth based based on
+ * preferences and the origin
+ */
+ScrollMode GetScrollModeForOrigin(ScrollOrigin origin);
+
+}  // namespace apz
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif  // mozilla_layers_APZPublicUtils_h