/* -*- 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/. */

/*
 * structs that contain the data provided by ComputedStyle, the
 * internal API for computed style data for an element
 */

#ifndef nsStyleStruct_h___
#define nsStyleStruct_h___

#include "mozilla/Attributes.h"
#include "mozilla/Maybe.h"
#include "mozilla/SheetType.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/StyleComplexColor.h"
#include "mozilla/UniquePtr.h"
#include "nsColor.h"
#include "nsCoord.h"
#include "nsMargin.h"
#include "nsFont.h"
#include "nsStyleAutoArray.h"
#include "nsStyleCoord.h"
#include "nsStyleConsts.h"
#include "nsChangeHint.h"
#include "nsTimingFunction.h"
#include "nsCOMPtr.h"
#include "nsCOMArray.h"
#include "nsTArray.h"
#include "nsCSSValue.h"
#include "imgRequestProxy.h"
#include "Orientation.h"
#include "CounterStyleManager.h"
#include <cstddef> // offsetof()
#include <utility>
#include "X11UndefineNone.h"

class nsIFrame;
class nsIURI;
class nsTextFrame;
class imgIContainer;
class nsPresContext;
struct nsStyleDisplay;
struct nsStyleVisibility;
namespace mozilla {
class ComputedStyle;
namespace dom {
class ImageTracker;
} // namespace dom
} // namespace mozilla

namespace mozilla {

struct Position {
  using Coord = nsStyleCoord::CalcValue;

  Coord mXPosition, mYPosition;

  // Initialize nothing
  Position() {}

  // Sets both mXPosition and mYPosition to the given percent value for the
  // initial property-value (e.g. 0.0f for "0% 0%", or 0.5f for "50% 50%")
  void SetInitialPercentValues(float aPercentVal);

  // Sets both mXPosition and mYPosition to 0 (app units) for the
  // initial property-value as a length with no percentage component.
  void SetInitialZeroValues();

  // True if the effective background image position described by this depends
  // on the size of the corresponding frame.
  bool DependsOnPositioningAreaSize() const {
    return mXPosition.mPercent != 0.0f || mYPosition.mPercent != 0.0f;
  }

  bool operator==(const Position& aOther) const {
    return mXPosition == aOther.mXPosition &&
      mYPosition == aOther.mYPosition;
  }
  bool operator!=(const Position& aOther) const {
    return !(*this == aOther);
  }
};

} // namespace mozilla

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleFont
{
  nsStyleFont(const nsStyleFont& aStyleFont);
  explicit nsStyleFont(const nsPresContext* aContext);
  ~nsStyleFont() {
    MOZ_COUNT_DTOR(nsStyleFont);
  }
  void FinishStyle(nsPresContext*, const nsStyleFont*) {}
  const static bool kHasFinishStyle = false;

  nsChangeHint CalcDifference(const nsStyleFont& aNewData) const;

  /**
   * Return aSize multiplied by the current text zoom factor (in aPresContext).
   * aSize is allowed to be negative, but the caller is expected to deal with
   * negative results.  The result is clamped to nscoord_MIN .. nscoord_MAX.
   */
  static nscoord ZoomText(const nsPresContext* aPresContext, nscoord aSize);
  static already_AddRefed<nsAtom> GetLanguage(const nsPresContext* aPresContext);

  nsFont  mFont;
  nscoord mSize;        // Our "computed size". Can be different
                        // from mFont.size which is our "actual size" and is
                        // enforced to be >= the user's preferred min-size.
                        // mFont.size should be used for display purposes
                        // while mSize is the value to return in
                        // getComputedStyle() for example.

  // In stylo these three track whether the size is keyword-derived
  // and if so if it has been modified by a factor/offset
  float mFontSizeFactor;
  nscoord mFontSizeOffset;
  uint8_t mFontSizeKeyword; // NS_STYLE_FONT_SIZE_*, is NS_STYLE_FONT_SIZE_NO_KEYWORD
                            // when not keyword-derived

  uint8_t mGenericID;   // generic CSS font family, if any;
                        // value is a kGenericFont_* constant, see nsFont.h.

  // MathML scriptlevel support
  int8_t  mScriptLevel;
  // MathML  mathvariant support
  uint8_t mMathVariant;
  // MathML displaystyle support
  uint8_t mMathDisplay;

  // allow different min font-size for certain cases
  uint8_t mMinFontSizeRatio;     // percent * 100

  // was mLanguage set based on a lang attribute in the document?
  bool mExplicitLanguage;

  // should calls to ZoomText() and UnZoomText() be made to the font
  // size on this nsStyleFont?
  bool mAllowZoom;

  // The value mSize would have had if scriptminsize had never been applied
  nscoord mScriptUnconstrainedSize;
  nscoord mScriptMinSize;        // length
  float   mScriptSizeMultiplier;
  RefPtr<nsAtom> mLanguage;
};

struct nsStyleGradientStop
{
  nsStyleCoord mLocation; // percent, coord, calc, none
  mozilla::StyleComplexColor mColor;
  bool mIsInterpolationHint;

  // Use ==/!= on nsStyleGradient instead of on the gradient stop.
  bool operator==(const nsStyleGradientStop&) const = delete;
  bool operator!=(const nsStyleGradientStop&) const = delete;
};

class nsStyleGradient final
{
public:
  nsStyleGradient();
  uint8_t mShape;  // NS_STYLE_GRADIENT_SHAPE_*
  uint8_t mSize;   // NS_STYLE_GRADIENT_SIZE_*;
                   // not used (must be FARTHEST_CORNER) for linear shape
  bool mRepeating;
  bool mLegacySyntax; // If true, serialization should use a vendor prefix.
  // XXXdholbert This will hopefully be going away soon, if bug 1337655 sticks:
  bool mMozLegacySyntax; // (Only makes sense when mLegacySyntax is true.)
                         // If true, serialization should use -moz prefix.
                         // Else, serialization should use -webkit prefix.

  nsStyleCoord mBgPosX; // percent, coord, calc, none
  nsStyleCoord mBgPosY; // percent, coord, calc, none
  nsStyleCoord mAngle;  // none, angle

  nsStyleCoord mRadiusX; // percent, coord, calc, none
  nsStyleCoord mRadiusY; // percent, coord, calc, none

  // stops are in the order specified in the stylesheet
  nsTArray<nsStyleGradientStop> mStops;

  bool operator==(const nsStyleGradient& aOther) const;
  bool operator!=(const nsStyleGradient& aOther) const {
    return !(*this == aOther);
  }

  bool IsOpaque();
  bool HasCalc();
  uint32_t Hash(PLDHashNumber aHash);

  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(nsStyleGradient)

private:
  // Private destructor, to discourage deletion outside of Release():
  ~nsStyleGradient() {}

  nsStyleGradient(const nsStyleGradient& aOther) = delete;
  nsStyleGradient& operator=(const nsStyleGradient& aOther) = delete;
};

/**
 * A wrapper for an imgRequestProxy that supports off-main-thread creation
 * and equality comparison.
 *
 * An nsStyleImageRequest can be created using the constructor that takes the
 * URL, base URI, referrer and principal that can be used to initiate an image
 * load and produce an imgRequestProxy later.
 *
 * This can be called from any thread.  The nsStyleImageRequest is not
 * considered "resolved" at this point, and the Resolve() method must be called
 * later to initiate the image load and make calls to get() valid.
 *
 * Calls to TrackImage(), UntrackImage(), LockImage(), UnlockImage() and
 * RequestDiscard() are made to the imgRequestProxy and ImageTracker as
 * appropriate, according to the mode flags passed in to the constructor.
 *
 * The constructor receives a css::URLValue to represent the url()
 * information, which is held on to for the comparisons done in
 * DefinitelyEquals().
 */
class nsStyleImageRequest
{
public:
  // Flags describing whether the imgRequestProxy must be tracked in the
  // ImageTracker, whether LockImage/UnlockImage calls will be made
  // when obtaining and releasing the imgRequestProxy, and whether
  // RequestDiscard will be called on release.
  enum class Mode : uint8_t {
    // The imgRequestProxy will be added to the ImageTracker when resolved
    // Without this flag, the nsStyleImageRequest itself will call LockImage/
    // UnlockImage on the imgRequestProxy, rather than leaving locking to the
    // ImageTracker to manage.
    //
    // This flag is currently used by all nsStyleImageRequests except
    // those for list-style-image and cursor.
    Track = 0x1,

    // The imgRequestProxy will have its RequestDiscard method called when
    // the nsStyleImageRequest is going away.
    //
    // This is currently used only for cursor images.
    Discard = 0x2,
  };

  // Can be called from any thread, but Resolve() must be called later
  // on the main thread before get() can be used.
  nsStyleImageRequest(Mode aModeFlags, mozilla::css::URLValue* aImageValue);

  bool Resolve(nsPresContext*, const nsStyleImageRequest* aOldImageRequest);
  bool IsResolved() const { return mResolved; }

  imgRequestProxy* get() {
    MOZ_ASSERT(IsResolved(), "Resolve() must be called first");
    MOZ_ASSERT(NS_IsMainThread());
    return mRequestProxy.get();
  }
  const imgRequestProxy* get() const {
    return const_cast<nsStyleImageRequest*>(this)->get();
  }

  // Returns whether the URLValue objects in the two nsStyleImageRequests
  // return true from URLValue::DefinitelyEqualURIs.
  bool DefinitelyEquals(const nsStyleImageRequest& aOther) const;

  mozilla::css::URLValue* GetImageValue() const { return mImageValue; }

  already_AddRefed<nsIURI> GetImageURI() const;
  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(nsStyleImageRequest);

private:
  ~nsStyleImageRequest();
  nsStyleImageRequest& operator=(const nsStyleImageRequest& aOther) = delete;

  void MaybeTrackAndLock();

  RefPtr<imgRequestProxy> mRequestProxy;
  RefPtr<mozilla::css::URLValue> mImageValue;
  RefPtr<mozilla::dom::ImageTracker> mImageTracker;

  // Cache DocGroup for dispatching events in the destructor.
  RefPtr<mozilla::dom::DocGroup> mDocGroup;

  Mode mModeFlags;
  bool mResolved;
};

MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(nsStyleImageRequest::Mode)

enum nsStyleImageType {
  eStyleImageType_Null,
  eStyleImageType_Image,
  eStyleImageType_Gradient,
  eStyleImageType_Element,
  eStyleImageType_URL
};

struct CachedBorderImageData
{
  ~CachedBorderImageData() {
    PurgeCachedImages();
  }

  // Caller are expected to ensure that the value of aSVGViewportSize is
  // different from the cached one since the method won't do the check.
  void SetCachedSVGViewportSize(const mozilla::Maybe<nsSize>& aSVGViewportSize);
  const mozilla::Maybe<nsSize>& GetCachedSVGViewportSize();
  void PurgeCachedImages();
  void SetSubImage(uint8_t aIndex, imgIContainer* aSubImage);
  imgIContainer* GetSubImage(uint8_t aIndex);

private:
  // If this is a SVG border-image, we save the size of the SVG viewport that
  // we used when rasterizing any cached border-image subimages. (The viewport
  // size matters for percent-valued sizes & positions in inner SVG doc).
  mozilla::Maybe<nsSize> mCachedSVGViewportSize;
  nsCOMArray<imgIContainer> mSubImages;
};

/**
 * Represents a paintable image of one of the following types.
 * (1) A real image loaded from an external source.
 * (2) A CSS linear or radial gradient.
 * (3) An element within a document, or an <img>, <video>, or <canvas> element
 *     not in a document.
 * (*) Optionally a crop rect can be set to paint a partial (rectangular)
 * region of an image. (Currently, this feature is only supported with an
 * image of type (1)).
 */
struct nsStyleImage
{
  typedef mozilla::css::URLValue URLValue;

  nsStyleImage();
  ~nsStyleImage();
  nsStyleImage(const nsStyleImage& aOther);
  nsStyleImage& operator=(const nsStyleImage& aOther);

  void SetNull();
  void SetImageRequest(already_AddRefed<nsStyleImageRequest> aImage);
  void SetGradientData(nsStyleGradient* aGradient);
  void SetElementId(already_AddRefed<nsAtom> aElementId);
  void SetCropRect(mozilla::UniquePtr<nsStyleSides> aCropRect);
  void SetURLValue(already_AddRefed<URLValue> aData);

  void ResolveImage(nsPresContext* aContext, const nsStyleImage* aOldImage) {
    MOZ_ASSERT(mType != eStyleImageType_Image || mImage);
    if (mType == eStyleImageType_Image && !mImage->IsResolved()) {
      const nsStyleImageRequest* oldRequest =
        (aOldImage && aOldImage->GetType() == eStyleImageType_Image)
        ? aOldImage->ImageRequest() : nullptr;
      mImage->Resolve(aContext, oldRequest);
    }
  }

  nsStyleImageType GetType() const {
    return mType;
  }
  nsStyleImageRequest* ImageRequest() const {
    MOZ_ASSERT(mType == eStyleImageType_Image, "Data is not an image!");
    MOZ_ASSERT(mImage);
    return mImage;
  }
  imgRequestProxy* GetImageData() const {
    return ImageRequest()->get();
  }
  nsStyleGradient* GetGradientData() const {
    NS_ASSERTION(mType == eStyleImageType_Gradient, "Data is not a gradient!");
    return mGradient;
  }
  bool IsResolved() const {
    return mType != eStyleImageType_Image || ImageRequest()->IsResolved();
  }
  const nsAtom* GetElementId() const {
    NS_ASSERTION(mType == eStyleImageType_Element, "Data is not an element!");
    return mElementId;
  }
  const mozilla::UniquePtr<nsStyleSides>& GetCropRect() const {
    NS_ASSERTION(mType == eStyleImageType_Image,
                 "Only image data can have a crop rect");
    return mCropRect;
  }

  already_AddRefed<nsIURI> GetImageURI() const;

  URLValue* GetURLValue() const;

  /**
   * Compute the actual crop rect in pixels, using the source image bounds.
   * The computation involves converting percentage unit to pixel unit and
   * clamping each side value to fit in the source image bounds.
   * @param aActualCropRect the computed actual crop rect.
   * @param aIsEntireImage true iff |aActualCropRect| is identical to the
   * source image bounds.
   * @return true iff |aActualCropRect| holds a meaningful value.
   */
  bool ComputeActualCropRect(nsIntRect& aActualCropRect,
                               bool* aIsEntireImage = nullptr) const;

  /**
   * Starts the decoding of a image. Returns true if the current frame of the
   * image is complete. The return value is intended to be used instead of
   * IsComplete because IsComplete may not be up to date if notifications
   * from decoding are pending because they are being sent async.
   */
  bool StartDecoding() const;
  /**
   * @return true if the item is definitely opaque --- i.e., paints every
   * pixel within its bounds opaquely, and the bounds contains at least a pixel.
   */
  bool IsOpaque() const;
  /**
   * @return true if this image is fully loaded, and its size is calculated;
   * always returns true if |mType| is |eStyleImageType_Gradient| or
   * |eStyleImageType_Element|.
   */
  bool IsComplete() const;
  /**
   * @return true if this image is loaded without error;
   * always returns true if |mType| is |eStyleImageType_Gradient| or
   * |eStyleImageType_Element|.
   */
  bool IsLoaded() const;
  /**
   * @return true if it is 100% confident that this image contains no pixel
   * to draw.
   */
  bool IsEmpty() const {
    // There are some other cases when the image will be empty, for example
    // when the crop rect is empty. However, checking the emptiness of crop
    // rect is non-trivial since each side value can be specified with
    // percentage unit, which can not be evaluated until the source image size
    // is available. Therefore, we currently postpone the evaluation of crop
    // rect until the actual rendering time --- alternatively until GetOpaqueRegion()
    // is called.
    return mType == eStyleImageType_Null;
  }

  bool operator==(const nsStyleImage& aOther) const;
  bool operator!=(const nsStyleImage& aOther) const {
    return !(*this == aOther);
  }

  bool ImageDataEquals(const nsStyleImage& aOther) const
  {
    return GetType() == eStyleImageType_Image &&
           aOther.GetType() == eStyleImageType_Image &&
           GetImageData() == aOther.GetImageData();
  }

  // These methods are used for the caller to caches the sub images created
  // during a border-image paint operation
  inline void SetSubImage(uint8_t aIndex, imgIContainer* aSubImage) const;
  inline imgIContainer* GetSubImage(uint8_t aIndex) const;
  void PurgeCacheForViewportChange(
    const mozilla::Maybe<nsSize>& aSVGViewportSize,
    const bool aHasIntrinsicRatio) const;

private:
  void DoCopy(const nsStyleImage& aOther);
  void EnsureCachedBIData() const;

  // This variable keeps some cache data for border image and is lazily
  // allocated since it is only used in border image case.
  mozilla::UniquePtr<CachedBorderImageData> mCachedBIData;

  nsStyleImageType mType;
  union {
    nsStyleImageRequest* mImage;
    nsStyleGradient* mGradient;
    URLValue* mURLValue; // See the comment in SetStyleImage's 'case
                         // eCSSUnit_URL' section to know why we need to
                         // store URLValues separately from mImage.
    nsAtom* mElementId;
  };

  // This is _currently_ used only in conjunction with eStyleImageType_Image.
  mozilla::UniquePtr<nsStyleSides> mCropRect;
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleColor
{
  explicit nsStyleColor(const nsPresContext* aContext);
  nsStyleColor(const nsStyleColor& aOther);
  ~nsStyleColor() {
    MOZ_COUNT_DTOR(nsStyleColor);
  }
  void FinishStyle(nsPresContext*, const nsStyleColor*) {}
  const static bool kHasFinishStyle = false;

  nsChangeHint CalcDifference(const nsStyleColor& aNewData) const;

  // Don't add ANY members to this struct!  We can achieve caching in the rule
  // tree (rather than the style tree) by letting color stay by itself! -dwh
  nscolor mColor;
};

struct nsStyleImageLayers {
  // Indices into kBackgroundLayerTable and kMaskLayerTable
  enum {
    shorthand = 0,
    color,
    image,
    repeat,
    positionX,
    positionY,
    clip,
    origin,
    size,
    attachment,
    maskMode,
    composite
  };

  enum class LayerType : uint8_t {
    Background = 0,
    Mask
  };

  explicit nsStyleImageLayers(LayerType aType);
  nsStyleImageLayers(const nsStyleImageLayers &aSource);
  ~nsStyleImageLayers() {
    MOZ_COUNT_DTOR(nsStyleImageLayers);
  }

  static bool IsInitialPositionForLayerType(mozilla::Position aPosition, LayerType aType);

  struct Size {
    struct Dimension : public nsStyleCoord::CalcValue {
      nscoord ResolveLengthPercentage(nscoord aAvailable) const {
        double d = double(mPercent) * double(aAvailable) + double(mLength);
        if (d < 0.0) {
          return 0;
        }
        return NSToCoordRoundWithClamp(float(d));
      }
    };
    Dimension mWidth, mHeight;

    bool IsInitialValue() const {
      return mWidthType == eAuto && mHeightType == eAuto;
    }

    nscoord ResolveWidthLengthPercentage(const nsSize& aBgPositioningArea) const {
      MOZ_ASSERT(mWidthType == eLengthPercentage,
                 "resolving non-length/percent dimension!");
      return mWidth.ResolveLengthPercentage(aBgPositioningArea.width);
    }

    nscoord ResolveHeightLengthPercentage(const nsSize& aBgPositioningArea) const {
      MOZ_ASSERT(mHeightType == eLengthPercentage,
                 "resolving non-length/percent dimension!");
      return mHeight.ResolveLengthPercentage(aBgPositioningArea.height);
    }

    // Except for eLengthPercentage, Dimension types which might change
    // how a layer is painted when the corresponding frame's dimensions
    // change *must* precede all dimension types which are agnostic to
    // frame size; see DependsOnDependsOnPositioningAreaSizeSize.
    enum DimensionType {
      // If one of mWidth and mHeight is eContain or eCover, then both are.
      // NOTE: eContain and eCover *must* be equal to NS_STYLE_BG_SIZE_CONTAIN
      // and NS_STYLE_BG_SIZE_COVER (in kBackgroundSizeKTable).
      eContain, eCover,

      eAuto,
      eLengthPercentage,
      eDimensionType_COUNT
    };
    uint8_t mWidthType, mHeightType;

    // True if the effective image size described by this depends on the size of
    // the corresponding frame, when aImage (which must not have null type) is
    // the background image.
    bool DependsOnPositioningAreaSize(const nsStyleImage& aImage) const;

    // Initialize nothing
    Size() {}

    // Initialize to initial values
    void SetInitialValues();

    bool operator==(const Size& aOther) const;
    bool operator!=(const Size& aOther) const {
      return !(*this == aOther);
    }
  };

  struct Repeat {
    mozilla::StyleImageLayerRepeat mXRepeat, mYRepeat;

    // Initialize nothing
    Repeat() {}

    bool IsInitialValue() const {
      return mXRepeat == mozilla::StyleImageLayerRepeat::Repeat &&
             mYRepeat == mozilla::StyleImageLayerRepeat::Repeat;
    }

    bool DependsOnPositioningAreaSize() const {
      return mXRepeat == mozilla::StyleImageLayerRepeat::Space ||
             mYRepeat == mozilla::StyleImageLayerRepeat::Space;
    }

    // Initialize to initial values
    void SetInitialValues() {
      mXRepeat = mozilla::StyleImageLayerRepeat::Repeat;
      mYRepeat = mozilla::StyleImageLayerRepeat::Repeat;
    }

    bool operator==(const Repeat& aOther) const {
      return mXRepeat == aOther.mXRepeat &&
             mYRepeat == aOther.mYRepeat;
    }
    bool operator!=(const Repeat& aOther) const {
      return !(*this == aOther);
    }
  };

  struct Layer {
    typedef mozilla::StyleGeometryBox StyleGeometryBox;
    typedef mozilla::StyleImageLayerAttachment StyleImageLayerAttachment;

    nsStyleImage  mImage;
    mozilla::Position mPosition;
    Size          mSize;
    StyleGeometryBox  mClip;
    MOZ_INIT_OUTSIDE_CTOR StyleGeometryBox mOrigin;
    StyleImageLayerAttachment mAttachment;
                                  // background-only property
                                  // This property is used for background layer
                                  // only. For a mask layer, it should always
                                  // be the initial value, which is
                                  // StyleImageLayerAttachment::Scroll.
    uint8_t       mBlendMode;     // NS_STYLE_BLEND_*
                                  // background-only property
                                  // This property is used for background layer
                                  // only. For a mask layer, it should always
                                  // be the initial value, which is
                                  // NS_STYLE_BLEND_NORMAL.
    uint8_t       mComposite;     // NS_STYLE_MASK_COMPOSITE_*
                                  // mask-only property
                                  // This property is used for mask layer only.
                                  // For a background layer, it should always
                                  // be the initial value, which is
                                  // NS_STYLE_COMPOSITE_MODE_ADD.
    uint8_t       mMaskMode;      // NS_STYLE_MASK_MODE_*
                                  // mask-only property
                                  // This property is used for mask layer only.
                                  // For a background layer, it should always
                                  // be the initial value, which is
                                  // NS_STYLE_MASK_MODE_MATCH_SOURCE.
    Repeat        mRepeat;

    // This constructor does not initialize mRepeat or mOrigin and Initialize()
    // must be called to do that.
    Layer();
    ~Layer();

    // Initialize mRepeat and mOrigin by specified layer type
    void Initialize(LayerType aType);

    void ResolveImage(nsPresContext* aContext, const Layer* aOldLayer) {
      mImage.ResolveImage(aContext, aOldLayer ? &aOldLayer->mImage : nullptr);
    }

    // True if the rendering of this layer might change when the size
    // of the background positioning area changes.  This is true for any
    // non-solid-color background whose position or size depends on
    // the size of the positioning area.  It's also true for SVG images
    // whose root <svg> node has a viewBox.
    bool RenderingMightDependOnPositioningAreaSizeChange() const;

    // Compute the change hint required by changes in just this layer.
    nsChangeHint CalcDifference(const Layer& aNewLayer) const;

    // An equality operator that compares the images using URL-equality
    // rather than pointer-equality.
    bool operator==(const Layer& aOther) const;
    bool operator!=(const Layer& aOther) const {
      return !(*this == aOther);
    }
  };

  // The (positive) number of computed values of each property, since
  // the lengths of the lists are independent.
  uint32_t mAttachmentCount,
           mClipCount,
           mOriginCount,
           mRepeatCount,
           mPositionXCount,
           mPositionYCount,
           mImageCount,
           mSizeCount,
           mMaskModeCount,
           mBlendModeCount,
           mCompositeCount;

  // Layers are stored in an array, matching the top-to-bottom order in
  // which they are specified in CSS.  The number of layers to be used
  // should come from the background-image property.  We create
  // additional |Layer| objects for *any* property, not just
  // background-image.  This means that the bottommost layer that
  // callers in layout care about (which is also the one whose
  // background-clip applies to the background-color) may not be last
  // layer.  In layers below the bottom layer, properties will be
  // uninitialized unless their count, above, indicates that they are
  // present.
  nsStyleAutoArray<Layer> mLayers;

  const Layer& BottomLayer() const { return mLayers[mImageCount - 1]; }

  void ResolveImages(nsPresContext* aContext, const nsStyleImageLayers* aOldLayers) {
    for (uint32_t i = 0; i < mImageCount; ++i) {
      const Layer* oldLayer =
        (aOldLayers && aOldLayers->mLayers.Length() > i)
        ? &aOldLayers->mLayers[i]
        : nullptr;
      mLayers[i].ResolveImage(aContext, oldLayer);
    }
  }

  // Fill unspecified layers by cycling through their values
  // till they all are of length aMaxItemCount
  void FillAllLayers(uint32_t aMaxItemCount);

  nsChangeHint CalcDifference(const nsStyleImageLayers& aNewLayers,
                              nsStyleImageLayers::LayerType aType) const;

  nsStyleImageLayers& operator=(const nsStyleImageLayers& aOther);
  nsStyleImageLayers& operator=(nsStyleImageLayers&& aOther);
  bool operator==(const nsStyleImageLayers& aOther) const;

  static const nsCSSPropertyID kBackgroundLayerTable[];
  static const nsCSSPropertyID kMaskLayerTable[];

  #define NS_FOR_VISIBLE_IMAGE_LAYERS_BACK_TO_FRONT(var_, layers_) \
    for (uint32_t var_ = (layers_).mImageCount; var_-- != 0; )
  #define NS_FOR_VISIBLE_IMAGE_LAYERS_BACK_TO_FRONT_WITH_RANGE(var_, layers_, start_, count_) \
    NS_ASSERTION((int32_t)(start_) >= 0 && (uint32_t)(start_) < (layers_).mImageCount, "Invalid layer start!"); \
    NS_ASSERTION((count_) > 0 && (count_) <= (start_) + 1, "Invalid layer range!"); \
    for (uint32_t var_ = (start_) + 1; var_-- != (uint32_t)((start_) + 1 - (count_)); )
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleBackground {
  explicit nsStyleBackground(const nsPresContext* aContext);
  nsStyleBackground(const nsStyleBackground& aOther);
  ~nsStyleBackground();

  // Resolves and tracks the images in mImage.  Only called with a Servo-backed
  // style system, where those images must be resolved later than the OMT
  // nsStyleBackground constructor call.
  void FinishStyle(nsPresContext*, const nsStyleBackground*);
  const static bool kHasFinishStyle = true;

  nsChangeHint CalcDifference(const nsStyleBackground& aNewData) const;

  // Return the background color as nscolor.
  nscolor BackgroundColor(const nsIFrame* aFrame) const;
  nscolor BackgroundColor(mozilla::ComputedStyle* aStyle) const;

  // True if this background is completely transparent.
  bool IsTransparent(const nsIFrame* aFrame) const;
  bool IsTransparent(mozilla::ComputedStyle* aStyle) const;

  // We have to take slower codepaths for fixed background attachment,
  // but we don't want to do that when there's no image.
  // Not inline because it uses an nsCOMPtr<imgIRequest>
  // FIXME: Should be in nsStyleStructInlines.h.
  bool HasFixedBackground(nsIFrame* aFrame) const;

  // Checks to see if this has a non-empty image with "local" attachment.
  // This is defined in nsStyleStructInlines.h.
  inline bool HasLocalBackground() const;

  const nsStyleImageLayers::Layer& BottomLayer() const { return mImage.BottomLayer(); }

  nsStyleImageLayers mImage;
  mozilla::StyleComplexColor mBackgroundColor;
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleMargin
{
  explicit nsStyleMargin(const nsPresContext* aContext);
  nsStyleMargin(const nsStyleMargin& aMargin);
  ~nsStyleMargin() {
    MOZ_COUNT_DTOR(nsStyleMargin);
  }
  void FinishStyle(nsPresContext*, const nsStyleMargin*) {}
  const static bool kHasFinishStyle = false;

  nsChangeHint CalcDifference(const nsStyleMargin& aNewData) const;

  bool GetMargin(nsMargin& aMargin) const
  {
    if (!mMargin.ConvertsToLength()) {
      return false;
    }

    NS_FOR_CSS_SIDES(side) {
      aMargin.Side(side) = mMargin.ToLength(side);
    }
    return true;
  }

  // Return true if either the start or end side in the axis is 'auto'.
  // (defined in WritingModes.h since we need the full WritingMode type)
  inline bool HasBlockAxisAuto(mozilla::WritingMode aWM) const;
  inline bool HasInlineAxisAuto(mozilla::WritingMode aWM) const;

  nsStyleSides  mMargin; // coord, percent, calc, auto
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStylePadding
{
  explicit nsStylePadding(const nsPresContext* aContext);
  nsStylePadding(const nsStylePadding& aPadding);
  ~nsStylePadding() {
    MOZ_COUNT_DTOR(nsStylePadding);
  }
  void FinishStyle(nsPresContext*, const nsStylePadding*) {}
  const static bool kHasFinishStyle = false;

  nsChangeHint CalcDifference(const nsStylePadding& aNewData) const;

  nsStyleSides  mPadding;         // coord, percent, calc

  bool IsWidthDependent() const {
    return !mPadding.ConvertsToLength();
  }

  bool GetPadding(nsMargin& aPadding) const
  {
    if (!mPadding.ConvertsToLength()) {
      return false;
    }

    NS_FOR_CSS_SIDES(side) {
      // Clamp negative calc() to 0.
      aPadding.Side(side) = std::max(mPadding.ToLength(side), 0);
    }
    return true;
  }
};

struct nsCSSShadowItem
{
  nscoord mXOffset;
  nscoord mYOffset;
  nscoord mRadius;
  nscoord mSpread;

  mozilla::StyleComplexColor mColor;
  bool mInset;

  nsCSSShadowItem()
    : mXOffset(0)
    , mYOffset(0)
    , mRadius(0)
    , mSpread(0)
    , mColor(mozilla::StyleComplexColor::CurrentColor())
    , mInset(false)
  {
    MOZ_COUNT_CTOR(nsCSSShadowItem);
  }
  ~nsCSSShadowItem() {
    MOZ_COUNT_DTOR(nsCSSShadowItem);
  }

  bool operator==(const nsCSSShadowItem& aOther) const {
    return (mXOffset == aOther.mXOffset &&
            mYOffset == aOther.mYOffset &&
            mRadius == aOther.mRadius &&
            mSpread == aOther.mSpread &&
            mInset == aOther.mInset &&
            mColor == aOther.mColor);
  }
  bool operator!=(const nsCSSShadowItem& aOther) const {
    return !(*this == aOther);
  }
};

class nsCSSShadowArray final
{
public:
  void* operator new(size_t aBaseSize, uint32_t aArrayLen) {
    // We can allocate both this nsCSSShadowArray and the
    // actual array in one allocation. The amount of memory to
    // allocate is equal to the class's size + the number of bytes for all
    // but the first array item (because aBaseSize includes one
    // item, see the private declarations)
    return ::operator new(aBaseSize +
                          (aArrayLen - 1) * sizeof(nsCSSShadowItem));
  }

  void operator delete(void* aPtr) { ::operator delete(aPtr); }

  explicit nsCSSShadowArray(uint32_t aArrayLen) :
    mLength(aArrayLen)
  {
    for (uint32_t i = 1; i < mLength; ++i) {
      // Make sure we call the constructors of each nsCSSShadowItem
      // (the first one is called for us because we declared it under private)
      new (&mArray[i]) nsCSSShadowItem();
    }
  }

private:
  // Private destructor, to discourage deletion outside of Release():
  ~nsCSSShadowArray() {
    for (uint32_t i = 1; i < mLength; ++i) {
      mArray[i].~nsCSSShadowItem();
    }
  }

public:
  uint32_t Length() const { return mLength; }
  nsCSSShadowItem* ShadowAt(uint32_t i) {
    MOZ_ASSERT(i < mLength, "Accessing too high an index in the text shadow array!");
    return &mArray[i];
  }
  const nsCSSShadowItem* ShadowAt(uint32_t i) const {
    MOZ_ASSERT(i < mLength, "Accessing too high an index in the text shadow array!");
    return &mArray[i];
  }

  bool HasShadowWithInset(bool aInset) {
    for (uint32_t i = 0; i < mLength; ++i) {
      if (mArray[i].mInset == aInset) {
        return true;
      }
    }
    return false;
  }

  bool operator==(const nsCSSShadowArray& aOther) const {
    if (mLength != aOther.Length()) {
      return false;
    }

    for (uint32_t i = 0; i < mLength; ++i) {
      if (ShadowAt(i) != aOther.ShadowAt(i)) {
        return false;
      }
    }

    return true;
  }

  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(nsCSSShadowArray)

private:
  uint32_t mLength;
  nsCSSShadowItem mArray[1]; // This MUST be the last item
};

// Border widths are rounded to the nearest-below integer number of pixels,
// but values between zero and one device pixels are always rounded up to
// one device pixel.
#define NS_ROUND_BORDER_TO_PIXELS(l,tpp) \
  ((l) == 0) ? 0 : std::max((tpp), (l) / (tpp) * (tpp))

// Returns if the given border style type is visible or not
static bool IsVisibleBorderStyle(uint8_t aStyle)
{
  return (aStyle != NS_STYLE_BORDER_STYLE_NONE &&
          aStyle != NS_STYLE_BORDER_STYLE_HIDDEN);
}

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleBorder
{
  explicit nsStyleBorder(const nsPresContext* aContext);
  nsStyleBorder(const nsStyleBorder& aBorder);
  ~nsStyleBorder();

  // Resolves and tracks mBorderImageSource.  Only called with a Servo-backed
  // style system, where those images must be resolved later than the OMT
  // nsStyleBorder constructor call.
  void FinishStyle(nsPresContext*, const nsStyleBorder*);
  const static bool kHasFinishStyle = true;

  nsChangeHint CalcDifference(const nsStyleBorder& aNewData) const;

  // Return whether aStyle is a visible style.  Invisible styles cause
  // the relevant computed border width to be 0.
  // Note that this does *not* consider the effects of 'border-image':
  // if border-style is none, but there is a loaded border image,
  // HasVisibleStyle will be false even though there *is* a border.
  bool HasVisibleStyle(mozilla::Side aSide) const
  {
    return IsVisibleBorderStyle(mBorderStyle[aSide]);
  }

  // aBorderWidth is in twips
  void SetBorderWidth(mozilla::Side aSide, nscoord aBorderWidth)
  {
    nscoord roundedWidth =
      NS_ROUND_BORDER_TO_PIXELS(aBorderWidth, mTwipsPerPixel);
    mBorder.Side(aSide) = roundedWidth;
    if (HasVisibleStyle(aSide)) {
      mComputedBorder.Side(aSide) = roundedWidth;
    }
  }

  // Get the computed border (plus rounding).  This does consider the
  // effects of 'border-style: none', but does not consider
  // 'border-image'.
  const nsMargin& GetComputedBorder() const
  {
    return mComputedBorder;
  }

  bool HasBorder() const
  {
    return mComputedBorder != nsMargin(0,0,0,0) || !mBorderImageSource.IsEmpty();
  }

  // Get the actual border width for a particular side, in appunits.  Note that
  // this is zero if and only if there is no border to be painted for this
  // side.  That is, this value takes into account the border style and the
  // value is rounded to the nearest device pixel by NS_ROUND_BORDER_TO_PIXELS.
  nscoord GetComputedBorderWidth(mozilla::Side aSide) const
  {
    return GetComputedBorder().Side(aSide);
  }

  uint8_t GetBorderStyle(mozilla::Side aSide) const
  {
    NS_ASSERTION(aSide <= mozilla::eSideLeft, "bad side");
    return mBorderStyle[aSide];
  }

  void SetBorderStyle(mozilla::Side aSide, uint8_t aStyle)
  {
    NS_ASSERTION(aSide <= mozilla::eSideLeft, "bad side");
    mBorderStyle[aSide] = aStyle;
    mComputedBorder.Side(aSide) =
      (HasVisibleStyle(aSide) ? mBorder.Side(aSide) : 0);
  }

  inline bool IsBorderImageLoaded() const
  {
    return mBorderImageSource.IsLoaded();
  }

  nsMargin GetImageOutset() const;

  imgIRequest* GetBorderImageRequest() const
  {
    if (mBorderImageSource.GetType() == eStyleImageType_Image) {
      return mBorderImageSource.GetImageData();
    }
    return nullptr;
  }

public:
  nsStyleCorners mBorderRadius;       // coord, percent
  nsStyleImage   mBorderImageSource;
  nsStyleSides   mBorderImageSlice;   // factor, percent
  nsStyleSides   mBorderImageWidth;   // length, factor, percent, auto
  nsStyleSides   mBorderImageOutset;  // length, factor

  uint8_t        mBorderImageFill;
  mozilla::StyleBorderImageRepeat mBorderImageRepeatH;
  mozilla::StyleBorderImageRepeat mBorderImageRepeatV;
  mozilla::StyleFloatEdge mFloatEdge;
  mozilla::StyleBoxDecorationBreak mBoxDecorationBreak;

protected:
  uint8_t       mBorderStyle[4];  // NS_STYLE_BORDER_STYLE_*

public:
  // the colors to use for a simple border.
  // not used for -moz-border-colors
  mozilla::StyleComplexColor mBorderTopColor;
  mozilla::StyleComplexColor mBorderRightColor;
  mozilla::StyleComplexColor mBorderBottomColor;
  mozilla::StyleComplexColor mBorderLeftColor;

  mozilla::StyleComplexColor&
  BorderColorFor(mozilla::Side aSide) {
    switch (aSide) {
    case mozilla::eSideTop:    return mBorderTopColor;
    case mozilla::eSideRight:  return mBorderRightColor;
    case mozilla::eSideBottom: return mBorderBottomColor;
    case mozilla::eSideLeft:   return mBorderLeftColor;
    }
    MOZ_ASSERT_UNREACHABLE("Unknown side");
    return mBorderTopColor;
  }

  const mozilla::StyleComplexColor&
  BorderColorFor(mozilla::Side aSide) const {
    switch (aSide) {
    case mozilla::eSideTop:    return mBorderTopColor;
    case mozilla::eSideRight:  return mBorderRightColor;
    case mozilla::eSideBottom: return mBorderBottomColor;
    case mozilla::eSideLeft:   return mBorderLeftColor;
    }
    MOZ_ASSERT_UNREACHABLE("Unknown side");
    return mBorderTopColor;
  }

  static mozilla::StyleComplexColor nsStyleBorder::*
  BorderColorFieldFor(mozilla::Side aSide) {
    switch (aSide) {
      case mozilla::eSideTop:
        return &nsStyleBorder::mBorderTopColor;
      case mozilla::eSideRight:
        return &nsStyleBorder::mBorderRightColor;
      case mozilla::eSideBottom:
        return &nsStyleBorder::mBorderBottomColor;
      case mozilla::eSideLeft:
        return &nsStyleBorder::mBorderLeftColor;
    }
    MOZ_ASSERT_UNREACHABLE("Unknown side");
    return nullptr;
  }

protected:
  // mComputedBorder holds the CSS2.1 computed border-width values.
  // In particular, these widths take into account the border-style
  // for the relevant side, and the values are rounded to the nearest
  // device pixel (which is not part of the definition of computed
  // values). The presence or absence of a border-image does not
  // affect border-width values.
  nsMargin      mComputedBorder;

  // mBorder holds the nscoord values for the border widths as they
  // would be if all the border-style values were visible (not hidden
  // or none).  This member exists so that when we create structs
  // using the copy constructor during style resolution the new
  // structs will know what the specified values of the border were in
  // case they have more specific rules setting the border style.
  //
  // Note that this isn't quite the CSS specified value, since this
  // has had the enumerated border widths converted to lengths, and
  // all lengths converted to twips.  But it's not quite the computed
  // value either. The values are rounded to the nearest device pixel.
  nsMargin      mBorder;

private:
  nscoord       mTwipsPerPixel;

  nsStyleBorder& operator=(const nsStyleBorder& aOther) = delete;
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleOutline
{
  explicit nsStyleOutline(const nsPresContext* aContext);
  nsStyleOutline(const nsStyleOutline& aOutline);
  ~nsStyleOutline() {
    MOZ_COUNT_DTOR(nsStyleOutline);
  }
  void FinishStyle(nsPresContext*, const nsStyleOutline*) {}
  const static bool kHasFinishStyle = false;

  void RecalcData();
  nsChangeHint CalcDifference(const nsStyleOutline& aNewData) const;

  nsStyleCorners  mOutlineRadius; // coord, percent, calc

  // This is the specified value of outline-width, but with length values
  // computed to absolute.  mActualOutlineWidth stores the outline-width
  // value used by layout.  (We must store mOutlineWidth for the same
  // style struct resolution reasons that we do nsStyleBorder::mBorder;
  // see that field's comment.)
  nscoord       mOutlineWidth;
  nscoord       mOutlineOffset;
  mozilla::StyleComplexColor mOutlineColor;
  uint8_t       mOutlineStyle;  // NS_STYLE_BORDER_STYLE_*

  nscoord GetOutlineWidth() const
  {
    return mActualOutlineWidth;
  }

  bool ShouldPaintOutline() const
  {
    return mOutlineStyle == NS_STYLE_BORDER_STYLE_AUTO ||
           (GetOutlineWidth() > 0 &&
            mOutlineStyle != NS_STYLE_BORDER_STYLE_NONE);
  }

protected:
  // The actual value of outline-width is the computed value (an absolute
  // length, forced to zero when outline-style is none) rounded to device
  // pixels.  This is the value used by layout.
  nscoord       mActualOutlineWidth;
  nscoord       mTwipsPerPixel;
};


/**
 * An object that allows sharing of arrays that store 'quotes' property
 * values.  This is particularly important for inheritance, where we want
 * to share the same 'quotes' value with a parent ComputedStyle.
 */
class nsStyleQuoteValues
{
public:
  typedef nsTArray<std::pair<nsString, nsString>> QuotePairArray;
  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(nsStyleQuoteValues);
  QuotePairArray mQuotePairs;

private:
  ~nsStyleQuoteValues() {}
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleList
{
  explicit nsStyleList(const nsPresContext* aContext);
  nsStyleList(const nsStyleList& aStyleList);
  ~nsStyleList();

  void FinishStyle(nsPresContext*, const nsStyleList*);
  const static bool kHasFinishStyle = true;

  nsChangeHint CalcDifference(const nsStyleList& aNewData,
                              const nsStyleDisplay* aOldDisplay) const;

  static void Shutdown()
  {
    sInitialQuotes = nullptr;
  }

  imgRequestProxy* GetListStyleImage() const
  {
    return mListStyleImage ? mListStyleImage->get() : nullptr;
  }

  already_AddRefed<nsIURI> GetListStyleImageURI() const;

  const nsStyleQuoteValues::QuotePairArray& GetQuotePairs() const
  {
    return mQuotes->mQuotePairs;
  }

  uint8_t mListStylePosition;
  RefPtr<nsStyleImageRequest> mListStyleImage;

  mozilla::CounterStylePtr mCounterStyle;

private:
  RefPtr<nsStyleQuoteValues> mQuotes;
  nsStyleList& operator=(const nsStyleList& aOther) = delete;
public:
  nsRect        mImageRegion;           // the rect to use within an image

private:
  // nsStyleQuoteValues objects representing two common values, for sharing.
  static mozilla::StaticRefPtr<nsStyleQuoteValues> sInitialQuotes;
};

struct nsStyleGridLine
{
  // http://dev.w3.org/csswg/css-grid/#typedef-grid-line
  // XXXmats we could optimize memory size here
  bool mHasSpan;
  int32_t mInteger;  // 0 means not provided
  nsString mLineName;  // Empty string means not provided.

  // These are the limits that we choose to clamp grid line numbers to.
  // http://dev.w3.org/csswg/css-grid/#overlarge-grids
  // mInteger is clamped to this range:
  static const int32_t kMinLine = -10000;
  static const int32_t kMaxLine = 10000;

  nsStyleGridLine()
    : mHasSpan(false)
    , mInteger(0)
    // mLineName get its default constructor, the empty string
  {
  }

  nsStyleGridLine(const nsStyleGridLine& aOther)
  {
    (*this) = aOther;
  }

  void operator=(const nsStyleGridLine& aOther)
  {
    mHasSpan = aOther.mHasSpan;
    mInteger = aOther.mInteger;
    mLineName = aOther.mLineName;
  }

  bool operator!=(const nsStyleGridLine& aOther) const
  {
    return mHasSpan != aOther.mHasSpan ||
           mInteger != aOther.mInteger ||
           mLineName != aOther.mLineName;
  }

  bool IsAuto() const
  {
    bool haveInitialValues = mInteger == 0 && mLineName.IsEmpty();
    MOZ_ASSERT(!(haveInitialValues && mHasSpan),
               "should not have 'span' when other components are "
               "at their initial values");
    return haveInitialValues;
  }
};

// Computed value of the grid-template-columns or grid-template-rows property
// (but *not* grid-template-areas.)
// http://dev.w3.org/csswg/css-grid/#track-sizing
//
// This represents either:
// * none:
//   mIsSubgrid is false, all three arrays are empty
// * <track-list>:
//   mIsSubgrid is false,
//   mMinTrackSizingFunctions and mMaxTrackSizingFunctions
//   are of identical non-zero size,
//   and mLineNameLists is one element longer than that.
//   (Delimiting N columns requires N+1 lines:
//   one before each track, plus one at the very end.)
//
//   An omitted <line-names> is still represented in mLineNameLists,
//   as an empty sub-array.
//
//   A <track-size> specified as a single <track-breadth> is represented
//   as identical min and max sizing functions.
//   A 'fit-content(size)' <track-size> is represented as eStyleUnit_None
//   in the min sizing function and 'size' in the max sizing function.
//
//   The units for nsStyleCoord are:
//   * eStyleUnit_Percent represents a <percentage>
//   * eStyleUnit_FlexFraction represents a <flex> flexible fraction
//   * eStyleUnit_Coord represents a <length>
//   * eStyleUnit_Enumerated represents min-content or max-content
// * subgrid <line-name-list>?:
//   mIsSubgrid is true,
//   mLineNameLists may or may not be empty,
//   mMinTrackSizingFunctions and mMaxTrackSizingFunctions are empty.
//
// If mRepeatAutoIndex != -1 then that index is an <auto-repeat> and
// mIsAutoFill == true means it's an 'auto-fill', otherwise 'auto-fit'.
// mRepeatAutoLineNameListBefore is the list of line names before the track
// size, mRepeatAutoLineNameListAfter the names after.  (They are empty
// when there is no <auto-repeat> track, i.e. when mRepeatAutoIndex == -1).
// When mIsSubgrid is true, mRepeatAutoLineNameListBefore contains the line
// names and mRepeatAutoLineNameListAfter is empty.
struct nsStyleGridTemplate
{
  nsTArray<nsTArray<nsString>> mLineNameLists;
  nsTArray<nsStyleCoord> mMinTrackSizingFunctions;
  nsTArray<nsStyleCoord> mMaxTrackSizingFunctions;
  nsTArray<nsString> mRepeatAutoLineNameListBefore;
  nsTArray<nsString> mRepeatAutoLineNameListAfter;
  int16_t mRepeatAutoIndex; // -1 or the track index for an auto-fill/fit track
  bool mIsAutoFill : 1;
  bool mIsSubgrid : 1;

  nsStyleGridTemplate()
    : mRepeatAutoIndex(-1)
    , mIsAutoFill(false)
    , mIsSubgrid(false)
  {
  }

  inline bool operator==(const nsStyleGridTemplate& aOther) const {
    return
      mIsSubgrid == aOther.mIsSubgrid &&
      mLineNameLists == aOther.mLineNameLists &&
      mMinTrackSizingFunctions == aOther.mMinTrackSizingFunctions &&
      mMaxTrackSizingFunctions == aOther.mMaxTrackSizingFunctions &&
      mIsAutoFill == aOther.mIsAutoFill &&
      mRepeatAutoIndex == aOther.mRepeatAutoIndex &&
      mRepeatAutoLineNameListBefore == aOther.mRepeatAutoLineNameListBefore &&
      mRepeatAutoLineNameListAfter == aOther.mRepeatAutoLineNameListAfter;
  }

  bool HasRepeatAuto() const {
    return mRepeatAutoIndex != -1;
  }

  bool IsRepeatAutoIndex(uint32_t aIndex) const {
    MOZ_ASSERT(aIndex < uint32_t(2*nsStyleGridLine::kMaxLine));
    return int32_t(aIndex) == mRepeatAutoIndex;
  }
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStylePosition
{
  explicit nsStylePosition(const nsPresContext* aContext);
  nsStylePosition(const nsStylePosition& aOther);
  ~nsStylePosition();
  void FinishStyle(nsPresContext*, const nsStylePosition*) {}
  const static bool kHasFinishStyle = false;

  nsChangeHint CalcDifference(const nsStylePosition& aNewData,
                              const nsStyleVisibility* aOldStyleVisibility) const;

  /**
   * Return the used value for 'align-self' given our parent ComputedStyle
   * aParent (or null for the root).
   */
  uint8_t UsedAlignSelf(mozilla::ComputedStyle* aParent) const;

  /**
   * Return the used value for 'justify-self' given our parent ComputedStyle
   * aParent (or null for the root).
   */
  uint8_t UsedJustifySelf(mozilla::ComputedStyle* aParent) const;

  mozilla::Position mObjectPosition;
  nsStyleSides  mOffset;                // coord, percent, calc, auto
  nsStyleCoord  mWidth;                 // coord, percent, enum, calc, auto
  nsStyleCoord  mMinWidth;              // coord, percent, enum, calc
  nsStyleCoord  mMaxWidth;              // coord, percent, enum, calc, none
  nsStyleCoord  mHeight;                // coord, percent, calc, auto
  nsStyleCoord  mMinHeight;             // coord, percent, calc
  nsStyleCoord  mMaxHeight;             // coord, percent, calc, none
  nsStyleCoord  mFlexBasis;             // coord, percent, enum, calc, auto
  nsStyleCoord  mGridAutoColumnsMin;    // coord, percent, enum, calc, flex
  nsStyleCoord  mGridAutoColumnsMax;    // coord, percent, enum, calc, flex
  nsStyleCoord  mGridAutoRowsMin;       // coord, percent, enum, calc, flex
  nsStyleCoord  mGridAutoRowsMax;       // coord, percent, enum, calc, flex
  uint8_t       mGridAutoFlow;          // NS_STYLE_GRID_AUTO_FLOW_*
  mozilla::StyleBoxSizing mBoxSizing;

  // All align/justify properties here take NS_STYLE_ALIGN_* values.
  uint16_t      mAlignContent;          // fallback value in the high byte
  uint8_t       mAlignItems;
  uint8_t       mAlignSelf;
  uint16_t      mJustifyContent;        // fallback value in the high byte
  // We cascade mSpecifiedJustifyItems, to handle the auto value, but store the
  // computed value in mJustifyItems.
  //
  // They're effectively only different in this regard: mJustifyItems is set to
  // mSpecifiedJustifyItems, except when the latter is AUTO -- in that case,
  // mJustifyItems is set to NORMAL, or to the parent ComputedStyle's
  // mJustifyItems if it has the legacy flag.
  //
  // This last part happens in ComputedStyle::ApplyStyleFixups.
  uint8_t       mSpecifiedJustifyItems;
  uint8_t       mJustifyItems;
  uint8_t       mJustifySelf;
  uint8_t       mFlexDirection;         // NS_STYLE_FLEX_DIRECTION_*
  uint8_t       mFlexWrap;              // NS_STYLE_FLEX_WRAP_*
  uint8_t       mObjectFit;             // NS_STYLE_OBJECT_FIT_*
  int32_t       mOrder;
  float         mFlexGrow;
  float         mFlexShrink;
  nsStyleCoord  mZIndex;                // integer, auto
  mozilla::UniquePtr<nsStyleGridTemplate> mGridTemplateColumns;
  mozilla::UniquePtr<nsStyleGridTemplate> mGridTemplateRows;

  // nullptr for 'none'
  RefPtr<mozilla::css::GridTemplateAreasValue> mGridTemplateAreas;

  nsStyleGridLine mGridColumnStart;
  nsStyleGridLine mGridColumnEnd;
  nsStyleGridLine mGridRowStart;
  nsStyleGridLine mGridRowEnd;
  nsStyleCoord    mColumnGap;       // normal, coord, percent, calc
  nsStyleCoord    mRowGap;          // normal, coord, percent, calc

  bool OffsetHasPercent(mozilla::Side aSide) const
  {
    return mOffset.Get(aSide).HasPercent();
  }

  // Logical-coordinate accessors for width and height properties,
  // given a WritingMode value. The definitions of these methods are
  // found in WritingModes.h (after the WritingMode class is fully
  // declared).
  inline nsStyleCoord& ISize(mozilla::WritingMode aWM);
  inline nsStyleCoord& MinISize(mozilla::WritingMode aWM);
  inline nsStyleCoord& MaxISize(mozilla::WritingMode aWM);
  inline nsStyleCoord& BSize(mozilla::WritingMode aWM);
  inline nsStyleCoord& MinBSize(mozilla::WritingMode aWM);
  inline nsStyleCoord& MaxBSize(mozilla::WritingMode aWM);
  inline const nsStyleCoord& ISize(mozilla::WritingMode aWM) const;
  inline const nsStyleCoord& MinISize(mozilla::WritingMode aWM) const;
  inline const nsStyleCoord& MaxISize(mozilla::WritingMode aWM) const;
  inline const nsStyleCoord& BSize(mozilla::WritingMode aWM) const;
  inline const nsStyleCoord& MinBSize(mozilla::WritingMode aWM) const;
  inline const nsStyleCoord& MaxBSize(mozilla::WritingMode aWM) const;
  inline bool ISizeDependsOnContainer(mozilla::WritingMode aWM) const;
  inline bool MinISizeDependsOnContainer(mozilla::WritingMode aWM) const;
  inline bool MaxISizeDependsOnContainer(mozilla::WritingMode aWM) const;
  inline bool BSizeDependsOnContainer(mozilla::WritingMode aWM) const;
  inline bool MinBSizeDependsOnContainer(mozilla::WritingMode aWM) const;
  inline bool MaxBSizeDependsOnContainer(mozilla::WritingMode aWM) const;

  const nsStyleGridTemplate& GridTemplateColumns() const;
  const nsStyleGridTemplate& GridTemplateRows() const;

private:
  static bool ISizeCoordDependsOnContainer(const nsStyleCoord &aCoord)
  {
    return aCoord.HasPercent() ||
           (aCoord.GetUnit() == eStyleUnit_Enumerated &&
            (aCoord.GetIntValue() == NS_STYLE_WIDTH_FIT_CONTENT ||
             aCoord.GetIntValue() == NS_STYLE_WIDTH_AVAILABLE));
  }
  static bool BSizeCoordDependsOnContainer(const nsStyleCoord &aCoord)
  {
    return aCoord.HasPercent();
  }
};

struct nsStyleTextOverflowSide
{
  nsStyleTextOverflowSide() : mType(NS_STYLE_TEXT_OVERFLOW_CLIP) {}

  bool operator==(const nsStyleTextOverflowSide& aOther) const {
    return mType == aOther.mType &&
           (mType != NS_STYLE_TEXT_OVERFLOW_STRING ||
            mString == aOther.mString);
  }
  bool operator!=(const nsStyleTextOverflowSide& aOther) const {
    return !(*this == aOther);
  }

  nsString mString;
  uint8_t  mType;
};

struct nsStyleTextOverflow
{
  nsStyleTextOverflow() : mLogicalDirections(true) {}
  bool operator==(const nsStyleTextOverflow& aOther) const {
    return mLeft == aOther.mLeft && mRight == aOther.mRight;
  }
  bool operator!=(const nsStyleTextOverflow& aOther) const {
    return !(*this == aOther);
  }

  // Returns the value to apply on the left side.
  const nsStyleTextOverflowSide& GetLeft(uint8_t aDirection) const {
    NS_ASSERTION(aDirection == NS_STYLE_DIRECTION_LTR ||
                 aDirection == NS_STYLE_DIRECTION_RTL, "bad direction");
    return !mLogicalDirections || aDirection == NS_STYLE_DIRECTION_LTR ?
             mLeft : mRight;
  }

  // Returns the value to apply on the right side.
  const nsStyleTextOverflowSide& GetRight(uint8_t aDirection) const {
    NS_ASSERTION(aDirection == NS_STYLE_DIRECTION_LTR ||
                 aDirection == NS_STYLE_DIRECTION_RTL, "bad direction");
    return !mLogicalDirections || aDirection == NS_STYLE_DIRECTION_LTR ?
             mRight : mLeft;
  }

  // Returns the first value that was specified.
  const nsStyleTextOverflowSide* GetFirstValue() const {
    return mLogicalDirections ? &mRight : &mLeft;
  }

  // Returns the second value, or null if there was only one value specified.
  const nsStyleTextOverflowSide* GetSecondValue() const {
    return mLogicalDirections ? nullptr : &mRight;
  }

  nsStyleTextOverflowSide mLeft;  // start side when mLogicalDirections is true
  nsStyleTextOverflowSide mRight; // end side when mLogicalDirections is true
  bool mLogicalDirections;  // true when only one value was specified
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleTextReset
{
  explicit nsStyleTextReset(const nsPresContext* aContext);
  nsStyleTextReset(const nsStyleTextReset& aOther);
  ~nsStyleTextReset();
  void FinishStyle(nsPresContext*, const nsStyleTextReset*) {}
  const static bool kHasFinishStyle = false;

  // Note the difference between this and
  // ComputedStyle::HasTextDecorationLines.
  bool HasTextDecorationLines() const {
    return mTextDecorationLine != NS_STYLE_TEXT_DECORATION_LINE_NONE &&
           mTextDecorationLine != NS_STYLE_TEXT_DECORATION_LINE_OVERRIDE_ALL;
  }

  nsChangeHint CalcDifference(const nsStyleTextReset& aNewData) const;

  nsStyleTextOverflow mTextOverflow;    // enum, string

  uint8_t mTextDecorationLine;          // NS_STYLE_TEXT_DECORATION_LINE_*
  uint8_t mTextDecorationStyle;         // NS_STYLE_TEXT_DECORATION_STYLE_*
  uint8_t mUnicodeBidi;                 // NS_STYLE_UNICODE_BIDI_*
  nscoord mInitialLetterSink;           // 0 means normal
  float mInitialLetterSize;             // 0.0f means normal
  mozilla::StyleComplexColor mTextDecorationColor;
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleText
{
  explicit nsStyleText(const nsPresContext* aContext);
  nsStyleText(const nsStyleText& aOther);
  ~nsStyleText();
  void FinishStyle(nsPresContext*, const nsStyleText*) {}
  const static bool kHasFinishStyle = false;

  nsChangeHint CalcDifference(const nsStyleText& aNewData) const;

  uint8_t mTextAlign;                   // NS_STYLE_TEXT_ALIGN_*
  uint8_t mTextAlignLast;               // NS_STYLE_TEXT_ALIGN_*
  mozilla::StyleTextJustify mTextJustify;
  uint8_t mTextTransform;               // NS_STYLE_TEXT_TRANSFORM_*
  mozilla::StyleWhiteSpace mWhiteSpace;
  uint8_t mWordBreak;                   // NS_STYLE_WORDBREAK_*
  uint8_t mOverflowWrap;                // NS_STYLE_OVERFLOWWRAP_*
  mozilla::StyleHyphens mHyphens;
  uint8_t mRubyAlign;                   // NS_STYLE_RUBY_ALIGN_*
  uint8_t mRubyPosition;                // NS_STYLE_RUBY_POSITION_*
  uint8_t mTextSizeAdjust;              // NS_STYLE_TEXT_SIZE_ADJUST_*
  uint8_t mTextCombineUpright;          // NS_STYLE_TEXT_COMBINE_UPRIGHT_*
  uint8_t mControlCharacterVisibility;  // NS_STYLE_CONTROL_CHARACTER_VISIBILITY_*
  uint8_t mTextEmphasisPosition;        // NS_STYLE_TEXT_EMPHASIS_POSITION_*
  uint8_t mTextEmphasisStyle;           // NS_STYLE_TEXT_EMPHASIS_STYLE_*
  uint8_t mTextRendering;               // NS_STYLE_TEXT_RENDERING_*
  mozilla::StyleComplexColor mTextEmphasisColor;
  mozilla::StyleComplexColor mWebkitTextFillColor;
  mozilla::StyleComplexColor mWebkitTextStrokeColor;

  nsStyleCoord mTabSize;                // coord, factor, calc
  nsStyleCoord mWordSpacing;            // coord, percent, calc
  nsStyleCoord mLetterSpacing;          // coord, normal
  nsStyleCoord mLineHeight;             // coord, factor, normal
  nsStyleCoord mTextIndent;             // coord, percent, calc
  nscoord mWebkitTextStrokeWidth;       // coord

  RefPtr<nsCSSShadowArray> mTextShadow; // nullptr in case of a zero-length

  nsString mTextEmphasisStyleString;

  bool WhiteSpaceIsSignificant() const {
    return mWhiteSpace == mozilla::StyleWhiteSpace::Pre ||
           mWhiteSpace == mozilla::StyleWhiteSpace::PreWrap ||
           mWhiteSpace == mozilla::StyleWhiteSpace::PreSpace;
  }

  bool NewlineIsSignificantStyle() const {
    return mWhiteSpace == mozilla::StyleWhiteSpace::Pre ||
           mWhiteSpace == mozilla::StyleWhiteSpace::PreWrap ||
           mWhiteSpace == mozilla::StyleWhiteSpace::PreLine;
  }

  bool WhiteSpaceOrNewlineIsSignificant() const {
    return mWhiteSpace == mozilla::StyleWhiteSpace::Pre ||
           mWhiteSpace == mozilla::StyleWhiteSpace::PreWrap ||
           mWhiteSpace == mozilla::StyleWhiteSpace::PreLine ||
           mWhiteSpace == mozilla::StyleWhiteSpace::PreSpace;
  }

  bool TabIsSignificant() const {
    return mWhiteSpace == mozilla::StyleWhiteSpace::Pre ||
           mWhiteSpace == mozilla::StyleWhiteSpace::PreWrap;
  }

  bool WhiteSpaceCanWrapStyle() const {
    return mWhiteSpace == mozilla::StyleWhiteSpace::Normal ||
           mWhiteSpace == mozilla::StyleWhiteSpace::PreWrap ||
           mWhiteSpace == mozilla::StyleWhiteSpace::PreLine;
  }

  bool WordCanWrapStyle() const {
    return WhiteSpaceCanWrapStyle() &&
           mOverflowWrap == NS_STYLE_OVERFLOWWRAP_BREAK_WORD;
  }

  bool HasTextEmphasis() const {
    return !mTextEmphasisStyleString.IsEmpty();
  }

  bool HasWebkitTextStroke() const {
    return mWebkitTextStrokeWidth > 0;
  }

  // These are defined in nsStyleStructInlines.h.
  inline bool HasTextShadow() const;
  inline nsCSSShadowArray* GetTextShadow() const;

  // The aContextFrame argument on each of these is the frame this
  // style struct is for.  If the frame is for SVG text or inside ruby,
  // the return value will be massaged to be something that makes sense
  // for those cases.
  inline bool NewlineIsSignificant(const nsTextFrame* aContextFrame) const;
  inline bool WhiteSpaceCanWrap(const nsIFrame* aContextFrame) const;
  inline bool WordCanWrap(const nsIFrame* aContextFrame) const;

  mozilla::LogicalSide TextEmphasisSide(mozilla::WritingMode aWM) const;
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleVisibility
{
  explicit nsStyleVisibility(const nsPresContext* aContext);
  nsStyleVisibility(const nsStyleVisibility& aVisibility);
  ~nsStyleVisibility() {
    MOZ_COUNT_DTOR(nsStyleVisibility);
  }
  void FinishStyle(nsPresContext*, const nsStyleVisibility*) {}
  const static bool kHasFinishStyle = false;

  nsChangeHint CalcDifference(const nsStyleVisibility& aNewData) const;

  mozilla::StyleImageOrientation mImageOrientation;
  uint8_t mDirection;                  // NS_STYLE_DIRECTION_*
  uint8_t mVisible;                    // NS_STYLE_VISIBILITY_VISIBLE_*
  uint8_t mImageRendering;             // NS_STYLE_IMAGE_RENDERING_*
  uint8_t mWritingMode;                // NS_STYLE_WRITING_MODE_*
  uint8_t mTextOrientation;            // NS_STYLE_TEXT_ORIENTATION_MIXED_*
  uint8_t mColorAdjust;                // NS_STYLE_COLOR_ADJUST_ECONOMY_*

  bool IsVisible() const {
    return (mVisible == NS_STYLE_VISIBILITY_VISIBLE);
  }

  bool IsVisibleOrCollapsed() const {
    return ((mVisible == NS_STYLE_VISIBILITY_VISIBLE) ||
            (mVisible == NS_STYLE_VISIBILITY_COLLAPSE));
  }
};

namespace mozilla {

struct StyleTransition
{
  StyleTransition() { /* leaves uninitialized; see also SetInitialValues */ }
  explicit StyleTransition(const StyleTransition& aCopy);

  void SetInitialValues();

  // Delay and Duration are in milliseconds

  const nsTimingFunction& GetTimingFunction() const { return mTimingFunction; }
  float GetDelay() const { return mDelay; }
  float GetDuration() const { return mDuration; }
  nsCSSPropertyID GetProperty() const { return mProperty; }
  nsAtom* GetUnknownProperty() const { return mUnknownProperty; }

  bool operator==(const StyleTransition& aOther) const;
  bool operator!=(const StyleTransition& aOther) const
    { return !(*this == aOther); }

private:
  nsTimingFunction mTimingFunction;
  float mDuration;
  float mDelay;
  nsCSSPropertyID mProperty;
  RefPtr<nsAtom> mUnknownProperty; // used when mProperty is
                                      // eCSSProperty_UNKNOWN or
                                      // eCSSPropertyExtra_variable
};

struct StyleAnimation
{
  StyleAnimation() { /* leaves uninitialized; see also SetInitialValues */ }
  explicit StyleAnimation(const StyleAnimation& aCopy);

  void SetInitialValues();

  // Delay and Duration are in milliseconds

  const nsTimingFunction& GetTimingFunction() const { return mTimingFunction; }
  float GetDelay() const { return mDelay; }
  float GetDuration() const { return mDuration; }
  nsAtom* GetName() const { return mName; }
  dom::PlaybackDirection GetDirection() const { return mDirection; }
  dom::FillMode GetFillMode() const { return mFillMode; }
  StyleAnimationPlayState GetPlayState() const { return mPlayState; }
  float GetIterationCount() const { return mIterationCount; }

  void SetName(already_AddRefed<nsAtom> aName) { mName = aName; }
  void SetName(nsAtom* aName) { mName = aName; }

  bool operator==(const StyleAnimation& aOther) const;
  bool operator!=(const StyleAnimation& aOther) const
    { return !(*this == aOther); }

private:
  nsTimingFunction mTimingFunction;
  float mDuration;
  float mDelay;
  RefPtr<nsAtom> mName; // nsGkAtoms::_empty for 'none'
  dom::PlaybackDirection mDirection;
  dom::FillMode mFillMode;
  StyleAnimationPlayState mPlayState;
  float mIterationCount; // mozilla::PositiveInfinity<float>() means infinite
};

class StyleBasicShape final
{
public:
  explicit StyleBasicShape(StyleBasicShapeType type)
    : mType(type),
      mFillRule(StyleFillRule::Nonzero)
  {
    mPosition.SetInitialPercentValues(0.5f);
  }

  StyleBasicShapeType GetShapeType() const { return mType; }
  nsCSSKeyword GetShapeTypeName() const;

  StyleFillRule GetFillRule() const { return mFillRule; }

  const mozilla::Position& GetPosition() const {
    MOZ_ASSERT(mType == StyleBasicShapeType::Circle ||
               mType == StyleBasicShapeType::Ellipse,
               "expected circle or ellipse");
    return mPosition;
  }

  bool HasRadius() const
  {
    MOZ_ASSERT(mType == StyleBasicShapeType::Inset, "expected inset");
    nsStyleCoord zero;
    zero.SetCoordValue(0);
    NS_FOR_CSS_HALF_CORNERS(corner) {
      if (mRadius.Get(corner) != zero) {
        return true;
      }
    }
    return false;
  }

  const nsStyleCorners& GetRadius() const
  {
    MOZ_ASSERT(mType == StyleBasicShapeType::Inset, "expected inset");
    return mRadius;
  }

  // mCoordinates has coordinates for polygon or radii for
  // ellipse and circle.
  const nsTArray<nsStyleCoord>& Coordinates() const
  {
    return mCoordinates;
  }

  bool operator==(const StyleBasicShape& aOther) const
  {
    return mType == aOther.mType &&
           mFillRule == aOther.mFillRule &&
           mCoordinates == aOther.mCoordinates &&
           mPosition == aOther.mPosition &&
           mRadius == aOther.mRadius;
  }
  bool operator!=(const StyleBasicShape& aOther) const {
    return !(*this == aOther);
  }

private:
  StyleBasicShapeType mType;
  StyleFillRule mFillRule;

  // mCoordinates has coordinates for polygon or radii for
  // ellipse and circle.
  // (top, right, bottom, left) for inset
  nsTArray<nsStyleCoord> mCoordinates;
  // position of center for ellipse or circle
  mozilla::Position mPosition;
  // corner radii for inset (0 if not set)
  nsStyleCorners mRadius;
};

struct StyleSVGPath final
{
  const nsTArray<StylePathCommand>& Path() const
  {
    return mPath;
  }

  StyleFillRule FillRule() const
  {
    return mFillRule;
  }

  bool operator==(const StyleSVGPath& aOther) const
  {
    return mPath == aOther.mPath && mFillRule == aOther.mFillRule;
  }

  bool operator!=(const StyleSVGPath& aOther) const
  {
    return !(*this == aOther);
  }

private:
  nsTArray<StylePathCommand> mPath;
  StyleFillRule mFillRule = StyleFillRule::Nonzero;
};

struct StyleShapeSource final
{
  StyleShapeSource();

  StyleShapeSource(const StyleShapeSource& aSource);

  ~StyleShapeSource();

  StyleShapeSource& operator=(const StyleShapeSource& aOther);

  bool operator==(const StyleShapeSource& aOther) const;

  bool operator!=(const StyleShapeSource& aOther) const
  {
    return !(*this == aOther);
  }

  StyleShapeSourceType GetType() const
  {
    return mType;
  }

  css::URLValue* GetURL() const
  {
    MOZ_ASSERT(mType == StyleShapeSourceType::URL, "Wrong shape source type!");
    return mShapeImage
      ? static_cast<css::URLValue*>(mShapeImage->GetURLValue())
      : nullptr;
  }

  void SetURL(css::URLValue* aValue);

  const UniquePtr<nsStyleImage>& GetShapeImage() const
  {
    MOZ_ASSERT(mType == StyleShapeSourceType::Image, "Wrong shape source type!");
    return mShapeImage;
  }

  // Iff we have "shape-outside:<image>" with an image URI (not a gradient),
  // this method returns the corresponding imgIRequest*. Else, returns
  // null.
  imgIRequest* GetShapeImageData() const;

  void SetShapeImage(UniquePtr<nsStyleImage> aShapeImage);

  const UniquePtr<StyleBasicShape>& GetBasicShape() const
  {
    MOZ_ASSERT(mType == StyleShapeSourceType::Shape, "Wrong shape source type!");
    return mBasicShape;
  }

  void SetBasicShape(UniquePtr<StyleBasicShape> aBasicShape,
                     StyleGeometryBox aReferenceBox);

  StyleGeometryBox GetReferenceBox() const
  {
    MOZ_ASSERT(mType == StyleShapeSourceType::Box ||
               mType == StyleShapeSourceType::Shape,
               "Wrong shape source type!");
    return mReferenceBox;
  }

  void SetReferenceBox(StyleGeometryBox aReferenceBox);

  const StyleSVGPath* GetPath() const
  {
    MOZ_ASSERT(mType == StyleShapeSourceType::Path, "Wrong shape source type!");
    return mSVGPath.get();
  }
  void SetPath(UniquePtr<StyleSVGPath> aPath);

private:
  void* operator new(size_t) = delete;

  void DoCopy(const StyleShapeSource& aOther);
  void DoDestroy();

  union {
    mozilla::UniquePtr<StyleBasicShape> mBasicShape;
    mozilla::UniquePtr<nsStyleImage> mShapeImage;
    mozilla::UniquePtr<StyleSVGPath> mSVGPath;
    // TODO: Bug 1480665, implement ray() function.
  };
  StyleShapeSourceType mType = StyleShapeSourceType::None;
  StyleGeometryBox mReferenceBox = StyleGeometryBox::NoBox;
};

struct StyleMotion final
{
  bool operator==(const StyleMotion& aOther) const
  {
    return mOffsetPath == aOther.mOffsetPath;
  }

  bool operator!=(const StyleMotion& aOther) const
  {
    return !(*this == aOther);
  }

  const StyleShapeSource& OffsetPath() const
  {
    return mOffsetPath;
  }

  bool HasPath() const
  {
    // Bug 1186329: We have to check other acceptable types after supporting
    // different values of offset-path. e.g. basic-shapes, ray.
    return mOffsetPath.GetType() == StyleShapeSourceType::Path;
  }

private:
  StyleShapeSource mOffsetPath;
};

} // namespace mozilla

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleDisplay
{
  typedef mozilla::StyleGeometryBox StyleGeometryBox;

  explicit nsStyleDisplay(const nsPresContext* aContext);
  nsStyleDisplay(const nsStyleDisplay& aOther);
  ~nsStyleDisplay();

  void FinishStyle(nsPresContext*, const nsStyleDisplay*);
  const static bool kHasFinishStyle = true;

  nsChangeHint CalcDifference(const nsStyleDisplay& aNewData) const;

  // We guarantee that if mBinding is non-null, so are mBinding->GetURI() and
  // mBinding->mOriginPrincipal.
  RefPtr<mozilla::css::URLValue> mBinding;
  mozilla::StyleDisplay mDisplay;
  mozilla::StyleDisplay mOriginalDisplay;  // saved mDisplay for
                                           //         position:absolute/fixed
                                           //         and float:left/right;
                                           //         otherwise equal to
                                           //         mDisplay
  uint8_t mContain;             // NS_STYLE_CONTAIN_*
  mozilla::StyleAppearance mAppearance;
  uint8_t mPosition;            // NS_STYLE_POSITION_*

  mozilla::StyleFloat mFloat;
  // Save mFloat for position:absolute/fixed; otherwise equal to mFloat.
  mozilla::StyleFloat mOriginalFloat;

  mozilla::StyleClear mBreakType;
  uint8_t mBreakInside;         // NS_STYLE_PAGE_BREAK_AUTO/AVOID
  bool mBreakBefore;
  bool mBreakAfter;
  uint8_t mOverflowX;           // NS_STYLE_OVERFLOW_*
  uint8_t mOverflowY;           // NS_STYLE_OVERFLOW_*
  uint8_t mOverflowClipBoxBlock;     // NS_STYLE_OVERFLOW_CLIP_BOX_*
  uint8_t mOverflowClipBoxInline;    // NS_STYLE_OVERFLOW_CLIP_BOX_*
  uint8_t mResize;              // NS_STYLE_RESIZE_*
  mozilla::StyleOrient mOrient;
  uint8_t mIsolation;           // NS_STYLE_ISOLATION_*
  uint8_t mTopLayer;            // NS_STYLE_TOP_LAYER_*
  uint8_t mWillChangeBitField;  // NS_STYLE_WILL_CHANGE_*
                                // Stores a bitfield representation of the
                                // properties that are frequently queried. This
                                // should match mWillChange. Also tracks if any
                                // of the properties in the will-change list
                                // require a stacking context.
  nsTArray<RefPtr<nsAtom>> mWillChange;

  uint8_t mTouchAction;         // NS_STYLE_TOUCH_ACTION_*
  uint8_t mScrollBehavior;      // NS_STYLE_SCROLL_BEHAVIOR_*
  mozilla::StyleOverscrollBehavior mOverscrollBehaviorX;
  mozilla::StyleOverscrollBehavior mOverscrollBehaviorY;
  uint8_t mScrollSnapTypeX;     // NS_STYLE_SCROLL_SNAP_TYPE_*
  uint8_t mScrollSnapTypeY;     // NS_STYLE_SCROLL_SNAP_TYPE_*
  nsStyleCoord mScrollSnapPointsX;
  nsStyleCoord mScrollSnapPointsY;
  mozilla::Position mScrollSnapDestination;
  nsTArray<mozilla::Position> mScrollSnapCoordinate;

  // mSpecifiedTransform is the list of transform functions as
  // specified, or null to indicate there is no transform.  (inherit or
  // initial are replaced by an actual list of transform functions, or
  // null, as appropriate.)
  uint8_t mBackfaceVisibility;
  uint8_t mTransformStyle;
  StyleGeometryBox mTransformBox;
  RefPtr<nsCSSValueSharedList> mSpecifiedTransform;
  RefPtr<nsCSSValueSharedList> mSpecifiedRotate;
  RefPtr<nsCSSValueSharedList> mSpecifiedTranslate;
  RefPtr<nsCSSValueSharedList> mSpecifiedScale;
  // Used to store the final combination of mSpecifiedRotate,
  // mSpecifiedTranslate, and mSpecifiedScale.
  RefPtr<nsCSSValueSharedList> mIndividualTransform;
  mozilla::UniquePtr<mozilla::StyleMotion> mMotion;

  nsStyleCoord mTransformOrigin[3]; // percent, coord, calc, 3rd param is coord, calc only
  nsStyleCoord mChildPerspective; // none, coord
  nsStyleCoord mPerspectiveOrigin[2]; // percent, coord, calc

  nsStyleCoord mVerticalAlign;  // coord, percent, calc, enum (NS_STYLE_VERTICAL_ALIGN_*)

  nsStyleAutoArray<mozilla::StyleTransition> mTransitions;

  // The number of elements in mTransitions that are not from repeating
  // a list due to another property being longer.
  uint32_t mTransitionTimingFunctionCount,
           mTransitionDurationCount,
           mTransitionDelayCount,
           mTransitionPropertyCount;

  nsCSSPropertyID GetTransitionProperty(uint32_t aIndex) const
  {
    return mTransitions[aIndex % mTransitionPropertyCount].GetProperty();
  }
  float GetTransitionDelay(uint32_t aIndex) const
  {
    return mTransitions[aIndex % mTransitionDelayCount].GetDelay();
  }
  float GetTransitionDuration(uint32_t aIndex) const
  {
    return mTransitions[aIndex % mTransitionDurationCount].GetDuration();
  }
  const nsTimingFunction& GetTransitionTimingFunction(uint32_t aIndex) const
  {
    return mTransitions[aIndex % mTransitionTimingFunctionCount].GetTimingFunction();
  }
  float GetTransitionCombinedDuration(uint32_t aIndex) const
  {
    // https://drafts.csswg.org/css-transitions/#transition-combined-duration
    return
      std::max(mTransitions[aIndex % mTransitionDurationCount].GetDuration(),
               0.0f)
        + mTransitions[aIndex % mTransitionDelayCount].GetDelay();
  }

  nsStyleAutoArray<mozilla::StyleAnimation> mAnimations;

  // The number of elements in mAnimations that are not from repeating
  // a list due to another property being longer.
  uint32_t mAnimationTimingFunctionCount,
           mAnimationDurationCount,
           mAnimationDelayCount,
           mAnimationNameCount,
           mAnimationDirectionCount,
           mAnimationFillModeCount,
           mAnimationPlayStateCount,
           mAnimationIterationCountCount;

  nsAtom* GetAnimationName(uint32_t aIndex) const
  {
    return mAnimations[aIndex % mAnimationNameCount].GetName();
  }
  float GetAnimationDelay(uint32_t aIndex) const
  {
    return mAnimations[aIndex % mAnimationDelayCount].GetDelay();
  }
  float GetAnimationDuration(uint32_t aIndex) const
  {
    return mAnimations[aIndex % mAnimationDurationCount].GetDuration();
  }
  mozilla::dom::PlaybackDirection GetAnimationDirection(uint32_t aIndex) const
  {
    return mAnimations[aIndex % mAnimationDirectionCount].GetDirection();
  }
  mozilla::dom::FillMode GetAnimationFillMode(uint32_t aIndex) const
  {
    return mAnimations[aIndex % mAnimationFillModeCount].GetFillMode();
  }
  mozilla::StyleAnimationPlayState GetAnimationPlayState(uint32_t aIndex) const
  {
    return mAnimations[aIndex % mAnimationPlayStateCount].GetPlayState();
  }
  float GetAnimationIterationCount(uint32_t aIndex) const
  {
    return mAnimations[aIndex % mAnimationIterationCountCount].GetIterationCount();
  }
  const nsTimingFunction& GetAnimationTimingFunction(uint32_t aIndex) const
  {
    return mAnimations[aIndex % mAnimationTimingFunctionCount].GetTimingFunction();
  }

  // The threshold used for extracting a shape from shape-outside: <image>.
  float mShapeImageThreshold = 0.0f;

  // The margin around a shape-outside: <image>.
  nsStyleCoord mShapeMargin;

  mozilla::StyleShapeSource mShapeOutside;

  bool HasAppearance() const
  {
    return mAppearance != mozilla::StyleAppearance::None;
  }

  bool IsBlockInsideStyle() const {
    return mozilla::StyleDisplay::Block == mDisplay ||
           mozilla::StyleDisplay::ListItem == mDisplay ||
           mozilla::StyleDisplay::InlineBlock == mDisplay ||
           mozilla::StyleDisplay::TableCaption == mDisplay ||
           mozilla::StyleDisplay::FlowRoot == mDisplay;
    // Should TABLE_CELL be included here?  They have
    // block frames nested inside of them.
    // (But please audit all callers before changing.)
  }

  bool IsBlockOutsideStyle() const {
    return mozilla::StyleDisplay::Block == mDisplay ||
           mozilla::StyleDisplay::Flex == mDisplay ||
           mozilla::StyleDisplay::WebkitBox == mDisplay ||
           mozilla::StyleDisplay::Grid == mDisplay ||
           mozilla::StyleDisplay::ListItem == mDisplay ||
           mozilla::StyleDisplay::Table == mDisplay ||
           mozilla::StyleDisplay::FlowRoot == mDisplay;
  }

  static bool IsDisplayTypeInlineOutside(mozilla::StyleDisplay aDisplay) {
    return mozilla::StyleDisplay::Inline == aDisplay ||
           mozilla::StyleDisplay::InlineBlock == aDisplay ||
           mozilla::StyleDisplay::InlineTable == aDisplay ||
           mozilla::StyleDisplay::MozInlineBox == aDisplay ||
           mozilla::StyleDisplay::InlineFlex == aDisplay ||
           mozilla::StyleDisplay::WebkitInlineBox == aDisplay ||
           mozilla::StyleDisplay::InlineGrid == aDisplay ||
           mozilla::StyleDisplay::MozInlineGrid == aDisplay ||
           mozilla::StyleDisplay::MozInlineStack == aDisplay ||
           mozilla::StyleDisplay::Ruby == aDisplay ||
           mozilla::StyleDisplay::RubyBase == aDisplay ||
           mozilla::StyleDisplay::RubyBaseContainer == aDisplay ||
           mozilla::StyleDisplay::RubyText == aDisplay ||
           mozilla::StyleDisplay::RubyTextContainer == aDisplay ||
           mozilla::StyleDisplay::Contents == aDisplay;
  }

  bool IsInlineOutsideStyle() const {
    return IsDisplayTypeInlineOutside(mDisplay);
  }

  bool IsOriginalDisplayInlineOutsideStyle() const {
    return IsDisplayTypeInlineOutside(mOriginalDisplay);
  }

  bool IsInnerTableStyle() const {
    return mozilla::StyleDisplay::TableCell == mDisplay ||
           IsInternalTableStyleExceptCell();
  }

  bool IsInternalTableStyleExceptCell() const {
    return mozilla::StyleDisplay::TableRow == mDisplay ||
           mozilla::StyleDisplay::TableRowGroup == mDisplay ||
           mozilla::StyleDisplay::TableHeaderGroup == mDisplay ||
           mozilla::StyleDisplay::TableFooterGroup == mDisplay ||
           mozilla::StyleDisplay::TableColumn == mDisplay ||
           mozilla::StyleDisplay::TableColumnGroup == mDisplay;
  }

  bool IsFloatingStyle() const {
    return mozilla::StyleFloat::None != mFloat;
  }

  bool IsAbsolutelyPositionedStyle() const {
    return NS_STYLE_POSITION_ABSOLUTE == mPosition ||
           NS_STYLE_POSITION_FIXED == mPosition;
  }

  bool IsRelativelyPositionedStyle() const {
    return NS_STYLE_POSITION_RELATIVE == mPosition ||
           NS_STYLE_POSITION_STICKY == mPosition;
  }
  bool IsPositionForcingStackingContext() const {
    return NS_STYLE_POSITION_STICKY == mPosition ||
           NS_STYLE_POSITION_FIXED == mPosition;
  }

  static bool IsRubyDisplayType(mozilla::StyleDisplay aDisplay) {
    return mozilla::StyleDisplay::Ruby == aDisplay ||
           IsInternalRubyDisplayType(aDisplay);
  }

  static bool IsInternalRubyDisplayType(mozilla::StyleDisplay aDisplay) {
    return mozilla::StyleDisplay::RubyBase == aDisplay ||
           mozilla::StyleDisplay::RubyBaseContainer == aDisplay ||
           mozilla::StyleDisplay::RubyText == aDisplay ||
           mozilla::StyleDisplay::RubyTextContainer == aDisplay;
  }

  bool IsRubyDisplayType() const {
    return IsRubyDisplayType(mDisplay);
  }

  bool IsInternalRubyDisplayType() const {
    return IsInternalRubyDisplayType(mDisplay);
  }

  bool IsOutOfFlowStyle() const {
    return (IsAbsolutelyPositionedStyle() || IsFloatingStyle());
  }

  bool IsScrollableOverflow() const {
    // mOverflowX and mOverflowY always match when one of them is
    // NS_STYLE_OVERFLOW_VISIBLE or NS_STYLE_OVERFLOW_CLIP.
    return mOverflowX != NS_STYLE_OVERFLOW_VISIBLE &&
           mOverflowX != NS_STYLE_OVERFLOW_CLIP;
  }

  bool IsContainPaint() const {
    return (NS_STYLE_CONTAIN_PAINT & mContain) &&
           !IsInternalRubyDisplayType() &&
           !IsInternalTableStyleExceptCell();
  }

  bool IsContainLayout() const {
    // Note: The spec for layout containment says it should
    // have no effect on non-atomic, inline-level boxes. We
    // don't check for these here because we don't know
    // what type of element is involved. Callers are
    // responsible for checking if the box in question is
    // non-atomic and inline-level, and creating an
    // exemption as necessary.
    return (NS_STYLE_CONTAIN_LAYOUT & mContain) &&
            !IsInternalRubyDisplayType() &&
            !IsInternalTableStyleExceptCell();
  }

  bool IsContainSize() const {
    // Note: The spec for size containment says it should
    // have no effect on non-atomic, inline-level boxes. We
    // don't check for these here because we don't know
    // what type of element is involved. Callers are
    // responsible for checking if the box in question is
    // non-atomic and inline-level, and creating an
    // exemption as necessary.
    return (NS_STYLE_CONTAIN_SIZE & mContain) &&
           !IsInternalRubyDisplayType() &&
           (mozilla::StyleDisplay::Table != mDisplay) &&
           !IsInnerTableStyle();
  }

  /* Returns whether the element has the -moz-transform property
   * or a related property. */
  bool HasTransformStyle() const {
    return mSpecifiedTransform || mSpecifiedRotate || mSpecifiedTranslate ||
           mSpecifiedScale ||
           mTransformStyle == NS_STYLE_TRANSFORM_STYLE_PRESERVE_3D ||
           (mWillChangeBitField & NS_STYLE_WILL_CHANGE_TRANSFORM) ||
           (mMotion && mMotion->HasPath());
  }

  bool HasIndividualTransform() const {
    return mSpecifiedRotate || mSpecifiedTranslate || mSpecifiedScale;
  }

  bool HasPerspectiveStyle() const {
    return mChildPerspective.GetUnit() == eStyleUnit_Coord;
  }

  bool BackfaceIsHidden() const {
    return mBackfaceVisibility == NS_STYLE_BACKFACE_VISIBILITY_HIDDEN;
  }

  // These are defined in nsStyleStructInlines.h.

  // The aContextFrame argument on each of these is the frame this
  // style struct is for.  If the frame is for SVG text, the return
  // value will be massaged to be something that makes sense for
  // SVG text.
  inline bool IsBlockInside(const nsIFrame* aContextFrame) const;
  inline bool IsBlockOutside(const nsIFrame* aContextFrame) const;
  inline bool IsInlineOutside(const nsIFrame* aContextFrame) const;
  inline bool IsOriginalDisplayInlineOutside(const nsIFrame* aContextFrame) const;
  inline mozilla::StyleDisplay GetDisplay(const nsIFrame* aContextFrame) const;
  inline bool IsFloating(const nsIFrame* aContextFrame) const;
  inline bool IsRelativelyPositioned(const nsIFrame* aContextFrame) const;
  inline bool IsAbsolutelyPositioned(const nsIFrame* aContextFrame) const;

  // These methods are defined in nsStyleStructInlines.h.

  /**
   * Returns true when the element has the transform property
   * or a related property, and supports CSS transforms.
   * aContextFrame is the frame for which this is the nsStyleDisplay.
   */
  inline bool HasTransform(const nsIFrame* aContextFrame) const;

  /**
   * Returns true when the element has the perspective property,
   * and supports CSS transforms. aContextFrame is the frame for
   * which this is the nsStyleDisplay.
   */
  inline bool HasPerspective(const nsIFrame* aContextFrame) const;

  /**
   * Returns whether the element is a containing block for its
   * absolutely positioned descendants.
   * aContextFrame is the frame for which this is the nsStyleDisplay.
   */
  inline bool IsAbsPosContainingBlock(const nsIFrame* aContextFrame) const;

  /**
   * Tests for only the sub-parts of IsAbsPosContainingBlock that apply
   * to nearly all frames, except those that are SVG text frames.
   *
   * This should be used only when the caller has the style but not the
   * frame (i.e., when calculating style changes).
   *
   * NOTE: This (unlike IsAbsPosContainingBlock) does not include
   * IsFixPosContainingBlockForNonSVGTextFrames.
   */
  inline bool IsAbsPosContainingBlockForNonSVGTextFrames() const;

  /**
   * Returns true when the element is a containing block for its fixed-pos
   * descendants.
   * aContextFrame is the frame for which this is the nsStyleDisplay.
   */
  inline bool IsFixedPosContainingBlock(const nsIFrame* aContextFrame) const;

  /**
   * Tests for only the sub-parts of IsFixedPosContainingBlock that apply
   * to:
   *  - nearly all frames, except those that are SVG text frames.
   *  - frames that support CSS contain:layout and contain:paint and are not
   *    SVG text frames.
   *  - frames that support CSS transforms and are not SVG text frames.
   *
   * This should be used only when the caller has the style but not the
   * frame (i.e., when calculating style changes).
   */
  inline bool IsFixedPosContainingBlockForNonSVGTextFrames(
    mozilla::ComputedStyle&) const;
  inline bool
    IsFixedPosContainingBlockForContainLayoutAndPaintSupportingFrames() const;
  inline bool IsFixedPosContainingBlockForTransformSupportingFrames() const;

  /**
   * Returns the final combined individual transform.
   **/
  already_AddRefed<nsCSSValueSharedList> GetCombinedTransform() const
  {
    return mIndividualTransform ? do_AddRef(mIndividualTransform) : nullptr;
  }

private:
  // Helpers for above functions, which do some but not all of the tests
  // for them (since transform must be tested separately for each).
  void GenerateCombinedIndividualTransform();
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleTable
{
  explicit nsStyleTable(const nsPresContext* aContext);
  nsStyleTable(const nsStyleTable& aOther);
  ~nsStyleTable();
  void FinishStyle(nsPresContext*, const nsStyleTable*) {}
  const static bool kHasFinishStyle = false;

  nsChangeHint CalcDifference(const nsStyleTable& aNewData) const;

  uint8_t mLayoutStrategy;  // NS_STYLE_TABLE_LAYOUT_*
  int32_t mSpan;  // -x-span; the number of columns spanned by a colgroup or col
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleTableBorder
{
  explicit nsStyleTableBorder(const nsPresContext* aContext);
  nsStyleTableBorder(const nsStyleTableBorder& aOther);
  ~nsStyleTableBorder();
  void FinishStyle(nsPresContext*, const nsStyleTableBorder*) {}
  const static bool kHasFinishStyle = false;

  nsChangeHint CalcDifference(const nsStyleTableBorder& aNewData) const;

  nscoord       mBorderSpacingCol;
  nscoord       mBorderSpacingRow;
  uint8_t       mBorderCollapse;
  uint8_t       mCaptionSide;
  uint8_t       mEmptyCells;
};

struct nsStyleContentAttr {
  RefPtr<nsAtom> mName; // Non-null.
  RefPtr<nsAtom> mNamespaceURL; // May be null.

  bool operator==(const nsStyleContentAttr& aOther) const
  {
    return mName == aOther.mName && mNamespaceURL == aOther.mNamespaceURL;
  }
};

class nsStyleContentData
{
  using StyleContentType = mozilla::StyleContentType;

public:
  nsStyleContentData()
    : mType(StyleContentType::Uninitialized)
  {
    MOZ_COUNT_CTOR(nsStyleContentData);
    mContent.mString = nullptr;
  }
  nsStyleContentData(const nsStyleContentData&);

  ~nsStyleContentData();
  nsStyleContentData& operator=(const nsStyleContentData& aOther);
  bool operator==(const nsStyleContentData& aOther) const;

  bool operator!=(const nsStyleContentData& aOther) const {
    return !(*this == aOther);
  }

  StyleContentType GetType() const { return mType; }

  char16_t* GetString() const
  {
    MOZ_ASSERT(mType == StyleContentType::String);
    return mContent.mString;
  }

  const nsStyleContentAttr* GetAttr() const {
    MOZ_ASSERT(mType == StyleContentType::Attr);
    MOZ_ASSERT(mContent.mAttr);
    return mContent.mAttr;
   }

  struct CounterFunction
  {
    nsString mIdent;
    // This is only used when it is a counters() function.
    nsString mSeparator;
    mozilla::CounterStylePtr mCounterStyle;

    NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CounterFunction)

    bool operator==(const CounterFunction& aOther) const;
    bool operator!=(const CounterFunction& aOther) const {
      return !(*this == aOther);
    }
  private:
    ~CounterFunction() {}
  };

  CounterFunction* GetCounters() const
  {
    MOZ_ASSERT(mType == StyleContentType::Counter ||
               mType == StyleContentType::Counters);
    MOZ_ASSERT(mContent.mCounters->mCounterStyle.IsResolved(),
               "Counter style should have been resolved");
    return mContent.mCounters;
  }

  nsStyleImageRequest* ImageRequest() const
  {
    MOZ_ASSERT(mType == StyleContentType::Image);
    MOZ_ASSERT(mContent.mImage);
    return mContent.mImage;
  }

  imgRequestProxy* GetImage() const
  {
    return ImageRequest()->get();
  }

  void SetCounters(StyleContentType aType,
                   already_AddRefed<CounterFunction> aCounterFunction)
  {
    MOZ_ASSERT(aType == StyleContentType::Counter ||
               aType == StyleContentType::Counters);
    MOZ_ASSERT(mType == StyleContentType::Uninitialized,
               "should only initialize nsStyleContentData once");
    mType = aType;
    mContent.mCounters = aCounterFunction.take();
    MOZ_ASSERT(mContent.mCounters);
  }

  void SetImageRequest(already_AddRefed<nsStyleImageRequest> aRequest)
  {
    MOZ_ASSERT(mType == StyleContentType::Uninitialized,
               "should only initialize nsStyleContentData once");
    mType = StyleContentType::Image;
    mContent.mImage = aRequest.take();
    MOZ_ASSERT(mContent.mImage);
  }

  void Resolve(nsPresContext*, const nsStyleContentData*);

private:
  StyleContentType mType;
  union {
    char16_t *mString;
    nsStyleContentAttr* mAttr;
    nsStyleImageRequest* mImage;
    CounterFunction* mCounters;
  } mContent;
};

struct nsStyleCounterData
{
  nsString  mCounter;
  int32_t   mValue;

  bool operator==(const nsStyleCounterData& aOther) const {
    return mValue == aOther.mValue && mCounter == aOther.mCounter;
  }

  bool operator!=(const nsStyleCounterData& aOther) const {
    return !(*this == aOther);
  }
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleContent
{
  explicit nsStyleContent(const nsPresContext* aContext);
  nsStyleContent(const nsStyleContent& aContent);
  ~nsStyleContent();
  void FinishStyle(nsPresContext*, const nsStyleContent*);
  const static bool kHasFinishStyle = true;

  nsChangeHint CalcDifference(const nsStyleContent& aNewData) const;

  uint32_t ContentCount() const { return mContents.Length(); }

  const nsStyleContentData& ContentAt(uint32_t aIndex) const {
    return mContents[aIndex];
  }

  nsStyleContentData& ContentAt(uint32_t aIndex) { return mContents[aIndex]; }

  void AllocateContents(uint32_t aCount) {
    // We need to run the destructors of the elements of mContents, so we
    // delete and reallocate even if aCount == mContentCount.  (If
    // nsStyleContentData had its members private and managed their
    // ownership on setting, we wouldn't need this, but that seems
    // unnecessary at this point.)
    mContents.Clear();
    mContents.SetLength(aCount);
  }

  uint32_t CounterIncrementCount() const { return mIncrements.Length(); }
  const nsStyleCounterData& CounterIncrementAt(uint32_t aIndex) const {
    return mIncrements[aIndex];
  }

  void AllocateCounterIncrements(uint32_t aCount) {
    mIncrements.Clear();
    mIncrements.SetLength(aCount);
  }

  void SetCounterIncrementAt(uint32_t aIndex, const nsString& aCounter, int32_t aIncrement) {
    mIncrements[aIndex].mCounter = aCounter;
    mIncrements[aIndex].mValue = aIncrement;
  }

  uint32_t CounterResetCount() const { return mResets.Length(); }
  const nsStyleCounterData& CounterResetAt(uint32_t aIndex) const {
    return mResets[aIndex];
  }

  void AllocateCounterResets(uint32_t aCount) {
    mResets.Clear();
    mResets.SetLength(aCount);
  }

  void SetCounterResetAt(uint32_t aIndex, const nsString& aCounter, int32_t aValue) {
    mResets[aIndex].mCounter = aCounter;
    mResets[aIndex].mValue = aValue;
  }

protected:
  nsTArray<nsStyleContentData> mContents;
  nsTArray<nsStyleCounterData> mIncrements;
  nsTArray<nsStyleCounterData> mResets;
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleUIReset
{
  explicit nsStyleUIReset(const nsPresContext* aContext);
  nsStyleUIReset(const nsStyleUIReset& aOther);
  ~nsStyleUIReset();
  void FinishStyle(nsPresContext*, const nsStyleUIReset*) {}
  const static bool kHasFinishStyle = false;

  nsChangeHint CalcDifference(const nsStyleUIReset& aNewData) const;

  mozilla::StyleUserSelect     mUserSelect;     // [reset](selection-style)
  mozilla::StyleScrollbarWidth mScrollbarWidth;
  uint8_t mForceBrokenImageIcon; // (0 if not forcing, otherwise forcing)
  uint8_t                      mIMEMode;
  mozilla::StyleWindowDragging mWindowDragging;
  uint8_t                      mWindowShadow;
  float                        mWindowOpacity;
  RefPtr<nsCSSValueSharedList> mSpecifiedWindowTransform;
  nsStyleCoord                 mWindowTransformOrigin[2]; // percent, coord, calc
};

struct nsCursorImage
{
  bool mHaveHotspot;
  float mHotspotX, mHotspotY;
  RefPtr<nsStyleImageRequest> mImage;

  nsCursorImage();
  nsCursorImage(const nsCursorImage& aOther);

  nsCursorImage& operator=(const nsCursorImage& aOther);

  bool operator==(const nsCursorImage& aOther) const;
  bool operator!=(const nsCursorImage& aOther) const
  {
    return !(*this == aOther);
  }

  imgRequestProxy* GetImage() const {
    return mImage->get();
  }
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleUI
{
  explicit nsStyleUI(const nsPresContext* aContext);
  nsStyleUI(const nsStyleUI& aOther);
  ~nsStyleUI();

  void FinishStyle(nsPresContext*, const nsStyleUI*);
  const static bool kHasFinishStyle = true;

  nsChangeHint CalcDifference(const nsStyleUI& aNewData) const;

  mozilla::StyleUserInput   mUserInput;
  mozilla::StyleUserModify  mUserModify;      // (modify-content)
  mozilla::StyleUserFocus   mUserFocus;       // (auto-select)
  uint8_t                   mPointerEvents;   // NS_STYLE_POINTER_EVENTS_*

  uint8_t mCursor;                            // NS_STYLE_CURSOR_*
  nsTArray<nsCursorImage> mCursorImages;      // images and coords
  mozilla::StyleComplexColor mCaretColor;

  mozilla::StyleComplexColor mScrollbarFaceColor;
  mozilla::StyleComplexColor mScrollbarTrackColor;

  inline uint8_t GetEffectivePointerEvents(nsIFrame* aFrame) const;

  bool HasCustomScrollbars() const
  {
    return !mScrollbarFaceColor.IsAuto() || !mScrollbarTrackColor.IsAuto();
  }
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleXUL
{
  explicit nsStyleXUL(const nsPresContext* aContext);
  nsStyleXUL(const nsStyleXUL& aSource);
  ~nsStyleXUL();
  void FinishStyle(nsPresContext*, const nsStyleXUL*) {}
  const static bool kHasFinishStyle = false;

  nsChangeHint CalcDifference(const nsStyleXUL& aNewData) const;

  float         mBoxFlex;
  uint32_t      mBoxOrdinal;
  mozilla::StyleBoxAlign mBoxAlign;
  mozilla::StyleBoxDirection mBoxDirection;
  mozilla::StyleBoxOrient mBoxOrient;
  mozilla::StyleBoxPack mBoxPack;
  mozilla::StyleStackSizing mStackSizing;
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleColumn
{
  explicit nsStyleColumn(const nsPresContext* aContext);
  nsStyleColumn(const nsStyleColumn& aSource);
  ~nsStyleColumn();
  void FinishStyle(nsPresContext*, const nsStyleColumn*) {}
  const static bool kHasFinishStyle = false;

  nsChangeHint CalcDifference(const nsStyleColumn& aNewData) const;

  // This is the maximum number of columns we can process. It's used in
  // nsColumnSetFrame.
  static const uint32_t kMaxColumnCount = 1000;

  // This represents the value of column-count: auto.
  static const uint32_t kColumnCountAuto = 0;

  uint32_t mColumnCount = kColumnCountAuto;
  nsStyleCoord mColumnWidth; // coord, auto

  mozilla::StyleComplexColor mColumnRuleColor;
  uint8_t      mColumnRuleStyle;  // NS_STYLE_BORDER_STYLE_*
  mozilla::StyleColumnFill mColumnFill = mozilla::StyleColumnFill::Balance;
  mozilla::StyleColumnSpan mColumnSpan = mozilla::StyleColumnSpan::None;

  nscoord GetComputedColumnRuleWidth() const {
    return (IsVisibleBorderStyle(mColumnRuleStyle) ? mColumnRuleWidth : 0);
  }

protected:
  nscoord mColumnRuleWidth;  // coord
  nscoord mTwipsPerPixel;
};

enum nsStyleSVGPaintType : uint8_t {
  eStyleSVGPaintType_None = 1,
  eStyleSVGPaintType_Color,
  eStyleSVGPaintType_Server,
  eStyleSVGPaintType_ContextFill,
  eStyleSVGPaintType_ContextStroke
};

enum nsStyleSVGFallbackType : uint8_t {
  eStyleSVGFallbackType_NotSet,
  eStyleSVGFallbackType_None,
  eStyleSVGFallbackType_Color,
};

enum nsStyleSVGOpacitySource : uint8_t {
  eStyleSVGOpacitySource_Normal,
  eStyleSVGOpacitySource_ContextFillOpacity,
  eStyleSVGOpacitySource_ContextStrokeOpacity
};

class nsStyleSVGPaint
{
public:
  explicit nsStyleSVGPaint(nsStyleSVGPaintType aType = nsStyleSVGPaintType(0));
  nsStyleSVGPaint(const nsStyleSVGPaint& aSource);
  ~nsStyleSVGPaint();

  nsStyleSVGPaint& operator=(const nsStyleSVGPaint& aOther);

  nsStyleSVGPaintType Type() const { return mType; }

  void SetNone();
  void SetColor(mozilla::StyleComplexColor aColor);
  void SetPaintServer(mozilla::css::URLValue* aPaintServer,
                      nsStyleSVGFallbackType aFallbackType,
                      mozilla::StyleComplexColor aFallbackColor);
  void SetPaintServer(mozilla::css::URLValue* aPaintServer) {
    SetPaintServer(aPaintServer, eStyleSVGFallbackType_NotSet,
                   mozilla::StyleComplexColor::Black());
  }
  void SetContextValue(nsStyleSVGPaintType aType,
                       nsStyleSVGFallbackType aFallbackType,
                       mozilla::StyleComplexColor aFallbackColor);
  void SetContextValue(nsStyleSVGPaintType aType) {
    SetContextValue(aType, eStyleSVGFallbackType_NotSet,
                    mozilla::StyleComplexColor::Black());
  }

  nscolor GetColor(mozilla::ComputedStyle* aComputedStyle) const {
    MOZ_ASSERT(mType == eStyleSVGPaintType_Color);
    return mPaint.mColor.CalcColor(aComputedStyle);
  }

  mozilla::css::URLValue* GetPaintServer() const {
    MOZ_ASSERT(mType == eStyleSVGPaintType_Server);
    return mPaint.mPaintServer;
  }

  nsStyleSVGFallbackType GetFallbackType() const {
    return mFallbackType;
  }

  nscolor GetFallbackColor(mozilla::ComputedStyle* aComputedStyle) const {
    MOZ_ASSERT(mType == eStyleSVGPaintType_Server ||
               mType == eStyleSVGPaintType_ContextFill ||
               mType == eStyleSVGPaintType_ContextStroke);
    return mFallbackColor.CalcColor(aComputedStyle);
  }

  bool operator==(const nsStyleSVGPaint& aOther) const;
  bool operator!=(const nsStyleSVGPaint& aOther) const {
    return !(*this == aOther);
  }

private:
  void Reset();
  void Assign(const nsStyleSVGPaint& aOther);

  union ColorOrPaintServer {
    mozilla::StyleComplexColor mColor;
    mozilla::css::URLValue* mPaintServer;
    explicit ColorOrPaintServer(mozilla::StyleComplexColor c) : mColor(c) {}
  };
  ColorOrPaintServer mPaint;
  nsStyleSVGPaintType mType;
  nsStyleSVGFallbackType mFallbackType;
  mozilla::StyleComplexColor mFallbackColor;
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleSVG
{
  explicit nsStyleSVG(const nsPresContext* aContext);
  nsStyleSVG(const nsStyleSVG& aSource);
  ~nsStyleSVG();
  void FinishStyle(nsPresContext*, const nsStyleSVG*) {}
  const static bool kHasFinishStyle = false;

  nsChangeHint CalcDifference(const nsStyleSVG& aNewData) const;

  nsStyleSVGPaint  mFill;
  nsStyleSVGPaint  mStroke;
  RefPtr<mozilla::css::URLValue> mMarkerEnd;
  RefPtr<mozilla::css::URLValue> mMarkerMid;
  RefPtr<mozilla::css::URLValue> mMarkerStart;
  nsTArray<nsStyleCoord> mStrokeDasharray;  // coord, percent, factor
  nsTArray<RefPtr<nsAtom>> mContextProps;

  nsStyleCoord     mStrokeDashoffset; // coord, percent, factor
  nsStyleCoord     mStrokeWidth;      // coord, percent, factor

  float            mFillOpacity;
  float            mStrokeMiterlimit;
  float            mStrokeOpacity;

  mozilla::StyleFillRule    mClipRule;
  uint8_t          mColorInterpolation; // NS_STYLE_COLOR_INTERPOLATION_*
  uint8_t          mColorInterpolationFilters; // NS_STYLE_COLOR_INTERPOLATION_*
  mozilla::StyleFillRule    mFillRule;
  uint8_t          mPaintOrder;       // bitfield of NS_STYLE_PAINT_ORDER_* values
  uint8_t          mShapeRendering;   // NS_STYLE_SHAPE_RENDERING_*
  uint8_t          mStrokeLinecap;    // NS_STYLE_STROKE_LINECAP_*
  uint8_t          mStrokeLinejoin;   // NS_STYLE_STROKE_LINEJOIN_*
  uint8_t          mTextAnchor;       // NS_STYLE_TEXT_ANCHOR_*
  uint8_t          mContextPropsBits; // bitfield of
                                      // NS_STYLE_CONTEXT_PROPERTY_FILL_* values

  /// Returns true if style has been set to expose the computed values of
  /// certain properties (such as 'fill') to the contents of any linked images.
  bool ExposesContextProperties() const {
    return bool(mContextPropsBits);
  }

  nsStyleSVGOpacitySource FillOpacitySource() const {
    uint8_t value = (mContextFlags & FILL_OPACITY_SOURCE_MASK) >>
                    FILL_OPACITY_SOURCE_SHIFT;
    return nsStyleSVGOpacitySource(value);
  }
  nsStyleSVGOpacitySource StrokeOpacitySource() const {
    uint8_t value = (mContextFlags & STROKE_OPACITY_SOURCE_MASK) >>
                    STROKE_OPACITY_SOURCE_SHIFT;
    return nsStyleSVGOpacitySource(value);
  }
  bool StrokeDasharrayFromObject() const {
    return mContextFlags & STROKE_DASHARRAY_CONTEXT;
  }
  bool StrokeDashoffsetFromObject() const {
    return mContextFlags & STROKE_DASHOFFSET_CONTEXT;
  }
  bool StrokeWidthFromObject() const {
    return mContextFlags & STROKE_WIDTH_CONTEXT;
  }

  bool HasMarker() const {
    return mMarkerStart || mMarkerMid || mMarkerEnd;
  }

  /**
   * Returns true if the stroke is not "none" and the stroke-opacity is greater
   * than zero. This ignores stroke-widths as that depends on the context.
   */
  bool HasStroke() const {
    return mStroke.Type() != eStyleSVGPaintType_None && mStrokeOpacity > 0;
  }

  /**
   * Returns true if the fill is not "none" and the fill-opacity is greater
   * than zero.
   */
  bool HasFill() const {
    return mFill.Type() != eStyleSVGPaintType_None && mFillOpacity > 0;
  }

private:
  // Flags to represent the use of context-fill and context-stroke
  // for fill-opacity or stroke-opacity, and context-value for stroke-dasharray,
  // stroke-dashoffset and stroke-width.

  // fill-opacity: context-{fill,stroke}
  static const uint8_t FILL_OPACITY_SOURCE_MASK   = 0x03;
  // stroke-opacity: context-{fill,stroke}
  static const uint8_t STROKE_OPACITY_SOURCE_MASK = 0x0C;
  // stroke-dasharray: context-value
  static const uint8_t STROKE_DASHARRAY_CONTEXT   = 0x10;
  // stroke-dashoffset: context-value
  static const uint8_t STROKE_DASHOFFSET_CONTEXT  = 0x20;
  // stroke-width: context-value
  static const uint8_t STROKE_WIDTH_CONTEXT       = 0x40;
  static const uint8_t FILL_OPACITY_SOURCE_SHIFT   = 0;
  static const uint8_t STROKE_OPACITY_SOURCE_SHIFT = 2;

  uint8_t          mContextFlags;
};

struct nsStyleFilter
{
  nsStyleFilter();
  nsStyleFilter(const nsStyleFilter& aSource);
  ~nsStyleFilter();
  void FinishStyle(nsPresContext*, const nsStyleFilter*) {}
  const static bool kHasFinishStyle = false;

  nsStyleFilter& operator=(const nsStyleFilter& aOther);

  bool operator==(const nsStyleFilter& aOther) const;
  bool operator!=(const nsStyleFilter& aOther) const {
    return !(*this == aOther);
  }

  uint32_t GetType() const {
    return mType;
  }

  const nsStyleCoord& GetFilterParameter() const {
    NS_ASSERTION(mType != NS_STYLE_FILTER_DROP_SHADOW &&
                 mType != NS_STYLE_FILTER_URL &&
                 mType != NS_STYLE_FILTER_NONE, "wrong filter type");
    return mFilterParameter;
  }
  void SetFilterParameter(const nsStyleCoord& aFilterParameter,
                          int32_t aType);

  mozilla::css::URLValue* GetURL() const {
    MOZ_ASSERT(mType == NS_STYLE_FILTER_URL, "wrong filter type");
    return mURL;
  }

  bool SetURL(mozilla::css::URLValue* aValue);

  nsCSSShadowArray* GetDropShadow() const {
    NS_ASSERTION(mType == NS_STYLE_FILTER_DROP_SHADOW, "wrong filter type");
    return mDropShadow;
  }
  void SetDropShadow(nsCSSShadowArray* aDropShadow);

private:
  void ReleaseRef();

  uint32_t mType; // NS_STYLE_FILTER_*
  nsStyleCoord mFilterParameter; // coord, percent, factor, angle
  union {
    mozilla::css::URLValue* mURL;
    nsCSSShadowArray* mDropShadow;
  };
};

template<>
struct nsTArray_CopyChooser<nsStyleFilter>
{
  typedef nsTArray_CopyWithConstructors<nsStyleFilter> Type;
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleSVGReset
{
  explicit nsStyleSVGReset(const nsPresContext* aContext);
  nsStyleSVGReset(const nsStyleSVGReset& aSource);
  ~nsStyleSVGReset();

  // Resolves and tracks the images in mMask.  Only called with a Servo-backed
  // style system, where those images must be resolved later than the OMT
  // nsStyleSVGReset constructor call.
  void FinishStyle(nsPresContext*, const nsStyleSVGReset*);
  const static bool kHasFinishStyle = true;

  nsChangeHint CalcDifference(const nsStyleSVGReset& aNewData) const;

  bool HasClipPath() const {
    return mClipPath.GetType() != mozilla::StyleShapeSourceType::None;
  }

  bool HasMask() const;

  bool HasNonScalingStroke() const {
    return mVectorEffect == NS_STYLE_VECTOR_EFFECT_NON_SCALING_STROKE;
  }

  nsStyleImageLayers    mMask;
  mozilla::StyleShapeSource mClipPath;
  mozilla::StyleComplexColor mStopColor;
  mozilla::StyleComplexColor mFloodColor;
  mozilla::StyleComplexColor mLightingColor;

  float            mStopOpacity;
  float            mFloodOpacity;

  uint8_t          mDominantBaseline; // NS_STYLE_DOMINANT_BASELINE_*
  uint8_t          mVectorEffect;     // NS_STYLE_VECTOR_EFFECT_*
  uint8_t          mMaskType;         // NS_STYLE_MASK_TYPE_*
};

struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleEffects
{
  explicit nsStyleEffects(const nsPresContext* aContext);
  nsStyleEffects(const nsStyleEffects& aSource);
  ~nsStyleEffects();
  void FinishStyle(nsPresContext*, const nsStyleEffects*) {}
  const static bool kHasFinishStyle = false;

  nsChangeHint CalcDifference(const nsStyleEffects& aNewData) const;

  bool HasFilters() const {
    return !mFilters.IsEmpty();
  }

  nsTArray<nsStyleFilter>  mFilters;
  RefPtr<nsCSSShadowArray> mBoxShadow; // nullptr for 'none'
  nsRect  mClip;                       // offsets from UL border edge
  float   mOpacity;
  uint8_t mClipFlags;                  // bitfield of NS_STYLE_CLIP_* values
  uint8_t mMixBlendMode;               // NS_STYLE_BLEND_*
};

#define STATIC_ASSERT_TYPE_LAYOUTS_MATCH(T1, T2)                               \
  static_assert(sizeof(T1) == sizeof(T2),                                      \
      "Size mismatch between " #T1 " and " #T2);                               \
  static_assert(alignof(T1) == alignof(T2),                                    \
      "Align mismatch between " #T1 " and " #T2);                              \

#define STATIC_ASSERT_FIELD_OFFSET_MATCHES(T1, T2, field)                      \
  static_assert(offsetof(T1, field) == offsetof(T2, field),                    \
      "Field offset mismatch of " #field " between " #T1 " and " #T2);         \

/**
 * These *_Simple types are used to map Gecko types to layout-equivalent but
 * simpler Rust types, to aid Rust binding generation.
 *
 * If something in this types or the assertions below needs to change, ask
 * bholley, heycam or emilio before!
 *
 * <div rustbindgen="true" replaces="nsPoint">
 */
struct nsPoint_Simple {
  nscoord x, y;
};

STATIC_ASSERT_TYPE_LAYOUTS_MATCH(nsPoint, nsPoint_Simple);
STATIC_ASSERT_FIELD_OFFSET_MATCHES(nsPoint, nsPoint_Simple, x);
STATIC_ASSERT_FIELD_OFFSET_MATCHES(nsPoint, nsPoint_Simple, y);

/**
 * <div rustbindgen="true" replaces="nsMargin">
 */
struct nsMargin_Simple {
  nscoord top, right, bottom, left;
};

STATIC_ASSERT_TYPE_LAYOUTS_MATCH(nsMargin, nsMargin_Simple);
STATIC_ASSERT_FIELD_OFFSET_MATCHES(nsMargin, nsMargin_Simple, top);
STATIC_ASSERT_FIELD_OFFSET_MATCHES(nsMargin, nsMargin_Simple, right);
STATIC_ASSERT_FIELD_OFFSET_MATCHES(nsMargin, nsMargin_Simple, bottom);
STATIC_ASSERT_FIELD_OFFSET_MATCHES(nsMargin, nsMargin_Simple, left);

/**
 * <div rustbindgen="true" replaces="nsRect">
 */
struct nsRect_Simple {
  nscoord x, y, width, height;
};

STATIC_ASSERT_TYPE_LAYOUTS_MATCH(nsRect, nsRect_Simple);
STATIC_ASSERT_FIELD_OFFSET_MATCHES(nsRect, nsRect_Simple, x);
STATIC_ASSERT_FIELD_OFFSET_MATCHES(nsRect, nsRect_Simple, y);
STATIC_ASSERT_FIELD_OFFSET_MATCHES(nsRect, nsRect_Simple, width);
STATIC_ASSERT_FIELD_OFFSET_MATCHES(nsRect, nsRect_Simple, height);

/**
 * <div rustbindgen="true" replaces="nsSize">
 */
struct nsSize_Simple {
  nscoord width, height;
};

STATIC_ASSERT_TYPE_LAYOUTS_MATCH(nsSize, nsSize_Simple);
STATIC_ASSERT_FIELD_OFFSET_MATCHES(nsSize, nsSize_Simple, width);
STATIC_ASSERT_FIELD_OFFSET_MATCHES(nsSize, nsSize_Simple, height);

/**
 * <div rustbindgen="true" replaces="mozilla::UniquePtr">
 *
 * TODO(Emilio): This is a workaround and we should be able to get rid of this
 * one.
 */
template<typename T>
struct UniquePtr_Simple {
  T* mPtr;
};

STATIC_ASSERT_TYPE_LAYOUTS_MATCH(mozilla::UniquePtr<int>, UniquePtr_Simple<int>);

/**
 * <div rustbindgen replaces="nsTArray"></div>
 */
template<typename T>
class nsTArray_Simple {
  T* mBuffer;
public:
  // The existence of a destructor here prevents bindgen from deriving the Clone
  // trait via a simple memory copy.
  ~nsTArray_Simple() {};
};

STATIC_ASSERT_TYPE_LAYOUTS_MATCH(nsTArray<nsStyleImageLayers::Layer>,
                                 nsTArray_Simple<nsStyleImageLayers::Layer>);
STATIC_ASSERT_TYPE_LAYOUTS_MATCH(nsTArray<mozilla::StyleTransition>,
                                 nsTArray_Simple<mozilla::StyleTransition>);
STATIC_ASSERT_TYPE_LAYOUTS_MATCH(nsTArray<mozilla::StyleAnimation>,
                                 nsTArray_Simple<mozilla::StyleAnimation>);

/**
 * <div rustbindgen replaces="nsCOMArray"></div>
 *
 * mozilla::ArrayIterator doesn't work well with bindgen.
 */
template<typename T>
class nsCOMArray_Simple {
  nsTArray<nsISupports*> mBuffer;
};

STATIC_ASSERT_TYPE_LAYOUTS_MATCH(nsCOMArray<nsIContent>,
                                 nsCOMArray_Simple<nsIContent>);
STATIC_ASSERT_TYPE_LAYOUTS_MATCH(nsCOMArray<nsINode>,
                                 nsCOMArray_Simple<nsINode>);
STATIC_ASSERT_TYPE_LAYOUTS_MATCH(nsCOMArray<imgIContainer>,
                                 nsCOMArray_Simple<imgIContainer>);

#endif /* nsStyleStruct_h___ */