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diff --git a/layout/base/nsCSSRenderingBorders.h b/layout/base/nsCSSRenderingBorders.h
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+++ b/layout/base/nsCSSRenderingBorders.h
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+// vim:cindent:ts=2:et:sw=2:
+/* 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 NS_CSS_RENDERING_BORDERS_H
+#define NS_CSS_RENDERING_BORDERS_H
+
+#include "gfxRect.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/BezierUtils.h"
+#include "mozilla/gfx/PathHelpers.h"
+#include "mozilla/RefPtr.h"
+#include "nsColor.h"
+#include "nsCOMPtr.h"
+#include "nsStyleConsts.h"
+#include "nsPresContext.h"
+
+struct nsBorderColors;
+
+namespace mozilla {
+namespace gfx {
+class GradientStops;
+} // namespace gfx
+} // namespace mozilla
+
+// define this to enable a bunch of debug dump info
+#undef DEBUG_NEW_BORDERS
+
+/*
+ * Helper class that handles border rendering.
+ *
+ * aDrawTarget -- the DrawTarget to which the border should be rendered
+ * outsideRect -- the rectangle on the outer edge of the border
+ *
+ * For any parameter where an array of side values is passed in,
+ * they are in top, right, bottom, left order.
+ *
+ * borderStyles -- one border style enum per side
+ * borderWidths -- one border width per side
+ * borderRadii -- a RectCornerRadii struct describing the w/h for each rounded corner.
+ *    If the corner doesn't have a border radius, 0,0 should be given for it.
+ * borderColors -- one nscolor per side
+ * compositeColors -- a pointer to an array of composite color structs, or
+ *    nullptr if none.
+ *
+ * skipSides -- a bit mask specifying which sides, if any, to skip
+ * backgroundColor -- the background color of the element.
+ *    Used in calculating colors for 2-tone borders, such as inset and outset
+ * gapRect - a rectangle that should be clipped out to leave a gap in a border,
+ *    or nullptr if none.
+ */
+
+typedef enum {
+  BorderColorStyleNone,
+  BorderColorStyleSolid,
+  BorderColorStyleLight,
+  BorderColorStyleDark
+} BorderColorStyle;
+
+class nsIDocument;
+class nsPresContext;
+
+class nsCSSBorderRenderer final
+{
+  typedef mozilla::gfx::Bezier Bezier;
+  typedef mozilla::gfx::ColorPattern ColorPattern;
+  typedef mozilla::gfx::DrawTarget DrawTarget;
+  typedef mozilla::gfx::Float Float;
+  typedef mozilla::gfx::Path Path;
+  typedef mozilla::gfx::Point Point;
+  typedef mozilla::gfx::Rect Rect;
+  typedef mozilla::gfx::RectCornerRadii RectCornerRadii;
+  typedef mozilla::gfx::StrokeOptions StrokeOptions;
+
+public:
+
+  nsCSSBorderRenderer(nsPresContext* aPresContext,
+                      const nsIDocument* aDocument,
+                      DrawTarget* aDrawTarget,
+                      const Rect& aDirtyRect,
+                      Rect& aOuterRect,
+                      const uint8_t* aBorderStyles,
+                      const Float* aBorderWidths,
+                      RectCornerRadii& aBorderRadii,
+                      const nscolor* aBorderColors,
+                      nsBorderColors* const* aCompositeColors,
+                      nscolor aBackgroundColor);
+
+  // draw the entire border
+  void DrawBorders();
+
+  // utility function used for background painting as well as borders
+  static void ComputeInnerRadii(const RectCornerRadii& aRadii,
+                                const Float* aBorderSizes,
+                                RectCornerRadii* aInnerRadiiRet);
+
+  // Given aRadii as the border radii for a rectangle, compute the
+  // appropriate radii for another rectangle *outside* that rectangle
+  // by increasing the radii, except keeping sharp corners sharp.
+  // Used for spread box-shadows
+  static void ComputeOuterRadii(const RectCornerRadii& aRadii,
+                                const Float* aBorderSizes,
+                                RectCornerRadii* aOuterRadiiRet);
+
+private:
+
+  RectCornerRadii mBorderCornerDimensions;
+
+  // Target document to report warning
+  nsPresContext* mPresContext;
+  const nsIDocument* mDocument;
+
+  // destination DrawTarget and dirty rect
+  DrawTarget* mDrawTarget;
+  const Rect& mDirtyRect;
+
+  // the rectangle of the outside and the inside of the border
+  Rect mOuterRect;
+  Rect mInnerRect;
+
+  // the style and size of the border
+  const uint8_t* mBorderStyles;
+  const Float* mBorderWidths;
+  RectCornerRadii mBorderRadii;
+
+  // colors
+  const nscolor* mBorderColors;
+  nsBorderColors* const* mCompositeColors;
+
+  // the background color
+  nscolor mBackgroundColor;
+
+  // calculated values
+  bool mOneUnitBorder;
+  bool mNoBorderRadius;
+  bool mAvoidStroke;
+
+  // For all the sides in the bitmask, would they be rendered
+  // in an identical color and style?
+  bool AreBorderSideFinalStylesSame(uint8_t aSides);
+
+  // For the given style, is the given corner a solid color?
+  bool IsSolidCornerStyle(uint8_t aStyle, mozilla::css::Corner aCorner);
+
+  // For the given corner, is the given corner mergeable into one dot?
+  bool IsCornerMergeable(mozilla::css::Corner aCorner);
+
+  // For the given solid corner, what color style should be used?
+  BorderColorStyle BorderColorStyleForSolidCorner(uint8_t aStyle, mozilla::css::Corner aCorner);
+
+  //
+  // Path generation functions
+  //
+
+  // Get the Rect for drawing the given corner
+  Rect GetCornerRect(mozilla::css::Corner aCorner);
+  // add the path for drawing the given side without any adjacent corners to the context
+  Rect GetSideClipWithoutCornersRect(mozilla::css::Side aSide);
+
+  // Create a clip path for the wedge that this side of
+  // the border should take up.  This is only called
+  // when we're drawing separate border sides, so we know
+  // that ADD compositing is taking place.
+  //
+  // This code needs to make sure that the individual pieces
+  // don't ever (mathematically) overlap; the pixel overlap
+  // is taken care of by the ADD compositing.
+  already_AddRefed<Path> GetSideClipSubPath(mozilla::css::Side aSide);
+
+  // Return start or end point for dashed/dotted side
+  Point GetStraightBorderPoint(mozilla::css::Side aSide,
+                               mozilla::css::Corner aCorner,
+                               bool* aIsUnfilled,
+                               Float aDotOffset = 0.0f);
+
+  // Return bezier control points for the outer and the inner curve for given
+  // corner
+  void GetOuterAndInnerBezier(Bezier* aOuterBezier,
+                              Bezier* aInnerBezier,
+                              mozilla::css::Corner aCorner);
+
+  // Given a set of sides to fill and a color, do so in the fastest way.
+  //
+  // Stroke tends to be faster for smaller borders because it doesn't go
+  // through the tessellator, which has initialization overhead.  If
+  // we're rendering all sides, we can use stroke at any thickness; we
+  // also do TL/BR pairs at 1px thickness using stroke.
+  //
+  // If we can't stroke, then if it's a TL/BR pair, we use the specific
+  // TL/BR paths.  Otherwise, we do the full path and fill.
+  //
+  // Calling code is expected to only set up a clip as necessary; no
+  // clip is needed if we can render the entire border in 1 or 2 passes.
+  void FillSolidBorder(const Rect& aOuterRect,
+                       const Rect& aInnerRect,
+                       const RectCornerRadii& aBorderRadii,
+                       const Float* aBorderSizes,
+                       int aSides,
+                       const ColorPattern& aColor);
+
+  //
+  // core rendering
+  //
+
+  // draw the border for the given sides, using the style of the first side
+  // present in the bitmask
+  void DrawBorderSides (int aSides);
+
+  // function used by the above to handle -moz-border-colors
+  void DrawBorderSidesCompositeColors(int aSides, const nsBorderColors *compositeColors);
+
+  // Setup the stroke options for the given dashed/dotted side
+  void SetupDashedOptions(StrokeOptions* aStrokeOptions,
+                          Float aDash[2], mozilla::css::Side aSide,
+                          Float aBorderLength, bool isCorner);
+
+  // Draw the given dashed/dotte side
+  void DrawDashedOrDottedSide(mozilla::css::Side aSide);
+
+  // Draw the given dotted side, each dot separately
+  void DrawDottedSideSlow(mozilla::css::Side aSide);
+
+  // Draw the given dashed/dotted corner
+  void DrawDashedOrDottedCorner(mozilla::css::Side aSide,
+                                mozilla::css::Corner aCorner);
+
+  // Draw the given dotted corner, each segment separately
+  void DrawDottedCornerSlow(mozilla::css::Side aSide,
+                            mozilla::css::Corner aCorner);
+
+  // Draw the given dashed corner, each dot separately
+  void DrawDashedCornerSlow(mozilla::css::Side aSide,
+                            mozilla::css::Corner aCorner);
+
+  // Draw the given dashed/dotted corner with solid style
+  void DrawFallbackSolidCorner(mozilla::css::Side aSide,
+                               mozilla::css::Corner aCorner);
+
+  // Analyze if all border sides have the same width.
+  bool AllBordersSameWidth();
+
+  // Analyze if all borders are 'solid' this also considers hidden or 'none'
+  // borders because they can be considered 'solid' borders of 0 width and
+  // with no color effect.
+  bool AllBordersSolid(bool *aHasCompositeColors);
+
+  // Draw a solid color border that is uniformly the same width.
+  void DrawSingleWidthSolidBorder();
+
+  // Draw any border which is solid on all sides and does not use
+  // CompositeColors.
+  void DrawNoCompositeColorSolidBorder();
+
+  // Draw a solid border that has no border radius (i.e. is rectangular) and
+  // uses CompositeColors.
+  void DrawRectangularCompositeColors();
+};
+
+namespace mozilla {
+#ifdef DEBUG_NEW_BORDERS
+#include <stdarg.h>
+
+static inline void PrintAsString(const mozilla::gfx::Point& p) {
+  fprintf (stderr, "[%f,%f]", p.x, p.y);
+}
+
+static inline void PrintAsString(const mozilla::gfx::Size& s) {
+  fprintf (stderr, "[%f %f]", s.width, s.height);
+}
+
+static inline void PrintAsString(const mozilla::gfx::Rect& r) {
+  fprintf (stderr, "[%f %f %f %f]", r.X(), r.Y(), r.Width(), r.Height());
+}
+
+static inline void PrintAsString(const mozilla::gfx::Float f) {
+  fprintf (stderr, "%f", f);
+}
+
+static inline void PrintAsString(const char *s) {
+  fprintf (stderr, "%s", s);
+}
+
+static inline void PrintAsStringNewline(const char *s = nullptr) {
+  if (s)
+    fprintf (stderr, "%s", s);
+  fprintf (stderr, "\n");
+  fflush (stderr);
+}
+
+static inline void PrintAsFormatString(const char *fmt, ...) {
+  va_list vl;
+  va_start(vl, fmt);
+  vfprintf (stderr, fmt, vl);
+  va_end(vl);
+}
+
+#else
+static inline void PrintAsString(const mozilla::gfx::Point& p) {}
+static inline void PrintAsString(const mozilla::gfx::Size& s) {}
+static inline void PrintAsString(const mozilla::gfx::Rect& r) {}
+static inline void PrintAsString(const mozilla::gfx::Float f) {}
+static inline void PrintAsString(const char *s) {}
+static inline void PrintAsStringNewline(const char *s = nullptr) {}
+static inline void PrintAsFormatString(const char *fmt, ...) {}
+#endif
+
+} // namespace mozilla
+
+#endif /* NS_CSS_RENDERING_BORDERS_H */