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diff --git a/layout/painting/nsCSSRenderingGradients.h b/layout/painting/nsCSSRenderingGradients.h
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+++ b/layout/painting/nsCSSRenderingGradients.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 nsCSSRenderingGradients_h__
+#define nsCSSRenderingGradients_h__
+
+#include "nsStyleStruct.h"
+#include "Units.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/webrender/webrender_ffi.h"
+
+namespace mozilla {
+
+namespace layers {
+class StackingContextHelper;
+}  // namespace layers
+
+namespace wr {
+class DisplayListBuilder;
+}  // namespace wr
+
+// A resolved color stop, with a specific position along the gradient line and
+// a color.
+struct ColorStop {
+  ColorStop() : mPosition(0), mIsMidpoint(false) {}
+  ColorStop(double aPosition, bool aIsMidPoint, const gfx::sRGBColor& aColor)
+      : mPosition(aPosition), mIsMidpoint(aIsMidPoint), mColor(aColor) {}
+  double mPosition;  // along the gradient line; 0=start, 1=end
+  bool mIsMidpoint;
+  gfx::sRGBColor mColor;
+};
+
+class nsCSSGradientRenderer final {
+ public:
+  /**
+   * Prepare a nsCSSGradientRenderer for a gradient for an element.
+   * aIntrinsicSize - the size of the source gradient.
+   */
+  static nsCSSGradientRenderer Create(nsPresContext* aPresContext,
+                                      ComputedStyle* aComputedStyle,
+                                      const StyleGradient& aGradient,
+                                      const nsSize& aIntrinsiceSize);
+
+  /**
+   * Draw the gradient to aContext
+   * aDest - where the first tile of gradient is
+   * aFill - the area to be filled with tiles of aDest
+   * aSrc - the area of the gradient that will fill aDest
+   * aRepeatSize - the distance from the origin of a tile
+   *               to the next origin of a tile
+   * aDirtyRect - pixels outside of this area may be skipped
+   */
+  void Paint(gfxContext& aContext, const nsRect& aDest, const nsRect& aFill,
+             const nsSize& aRepeatSize, const mozilla::CSSIntRect& aSrc,
+             const nsRect& aDirtyRect, float aOpacity = 1.0);
+
+  /**
+   * Collect the gradient parameters
+   */
+  void BuildWebRenderParameters(float aOpacity, wr::ExtendMode& aMode,
+                                nsTArray<wr::GradientStop>& aStops,
+                                LayoutDevicePoint& aLineStart,
+                                LayoutDevicePoint& aLineEnd,
+                                LayoutDeviceSize& aGradientRadius,
+                                LayoutDevicePoint& aGradientCenter,
+                                float& aGradientAngle);
+
+  /**
+   * Build display items for the gradient
+   * aLayer - the layer to make this display item relative to
+   * aDest - where the first tile of gradient is
+   * aFill - the area to be filled with tiles of aDest
+   * aRepeatSize - the distance from the origin of a tile
+   *               to the next origin of a tile
+   * aSrc - the area of the gradient that will fill aDest
+   */
+  void BuildWebRenderDisplayItems(wr::DisplayListBuilder& aBuilder,
+                                  const layers::StackingContextHelper& aSc,
+                                  const nsRect& aDest, const nsRect& aFill,
+                                  const nsSize& aRepeatSize,
+                                  const mozilla::CSSIntRect& aSrc,
+                                  bool aIsBackfaceVisible,
+                                  float aOpacity = 1.0);
+
+ private:
+  nsCSSGradientRenderer()
+      : mPresContext(nullptr),
+        mGradient(nullptr),
+        mRadiusX(0.0),
+        mRadiusY(0.0),
+        mAngle(0.0) {}
+
+  /**
+   * Attempts to paint the tiles for a gradient by painting it once to an
+   * offscreen surface and then painting that offscreen surface with
+   * ExtendMode::Repeat to cover all tiles.
+   *
+   * Returns false if the optimization wasn't able to be used, in which case
+   * a fallback should be used.
+   */
+  bool TryPaintTilesWithExtendMode(
+      gfxContext& aContext, gfxPattern* aGradientPattern, nscoord aXStart,
+      nscoord aYStart, const gfxRect& aDirtyAreaToFill, const nsRect& aDest,
+      const nsSize& aRepeatSize, bool aForceRepeatToCoverTiles);
+
+  nsPresContext* mPresContext;
+  const StyleGradient* mGradient;
+  nsTArray<ColorStop> mStops;
+  gfxPoint mLineStart, mLineEnd;  // only for linear/radial gradients
+  double mRadiusX, mRadiusY;      // only for radial gradients
+  gfxPoint mCenter;               // only for conic gradients
+  float mAngle;                   // only for conic gradients
+};
+
+}  // namespace mozilla
+
+#endif /* nsCSSRenderingGradients_h__ */