--- a/accessible/base/StyleInfo.h
+++ b/accessible/base/StyleInfo.h
@@ -17,31 +17,31 @@ class StyleInfo
 {
 public:
   StyleInfo(dom::Element* aElement, nsIPresShell* aPresShell);
   ~StyleInfo() { }
 
   void Display(nsAString& aValue);
   void TextAlign(nsAString& aValue);
   void TextIndent(nsAString& aValue);
-  void MarginLeft(nsAString& aValue) { Margin(eSideLeft, aValue); }
-  void MarginRight(nsAString& aValue) { Margin(eSideRight, aValue); }
-  void MarginTop(nsAString& aValue) { Margin(eSideTop, aValue); }
-  void MarginBottom(nsAString& aValue) { Margin(eSideBottom, aValue); }
+  void MarginLeft(nsAString& aValue) { Margin(css::eSideLeft, aValue); }
+  void MarginRight(nsAString& aValue) { Margin(css::eSideRight, aValue); }
+  void MarginTop(nsAString& aValue) { Margin(css::eSideTop, aValue); }
+  void MarginBottom(nsAString& aValue) { Margin(css::eSideBottom, aValue); }
 
   static void FormatColor(const nscolor& aValue, nsString& aFormattedValue);
   static void FormatFontStyle(const nscoord& aValue, nsAString& aFormattedValue);
   static void FormatTextDecorationStyle(uint8_t aValue, nsAString& aFormattedValue);
 
 private:
   StyleInfo() MOZ_DELETE;
   StyleInfo(const StyleInfo&) MOZ_DELETE;
   StyleInfo& operator = (const StyleInfo&) MOZ_DELETE;
 
-  void Margin(Side aSide, nsAString& aValue);
+  void Margin(css::Side aSide, nsAString& aValue);
 
   dom::Element* mElement;
   nsRefPtr<nsStyleContext> mStyleContext;
 };
 
 } // namespace a11y
 } // namespace mozilla
 

--- a/gfx/2d/BaseMargin.h
+++ b/gfx/2d/BaseMargin.h
@@ -4,76 +4,25 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef MOZILLA_GFX_BASEMARGIN_H_
 #define MOZILLA_GFX_BASEMARGIN_H_
 
 #include "Types.h"
 
 namespace mozilla {
-
-/**
- * Sides represents a set of physical sides.
- */
-struct Sides MOZ_FINAL {
-  Sides() : mBits(0) {}
-  explicit Sides(SideBits aSideBits)
-  {
-    MOZ_ASSERT((aSideBits & ~eSideBitsAll) == 0, "illegal side bits");
-    mBits = aSideBits;
-  }
-  bool IsEmpty() const { return mBits == 0; }
-  bool Top()     const { return mBits & eSideBitsTop; }
-  bool Right()   const { return mBits & eSideBitsRight; }
-  bool Bottom()  const { return mBits & eSideBitsBottom; }
-  bool Left()    const { return mBits & eSideBitsLeft; }
-  bool Contains(SideBits aSideBits) const
-  {
-    MOZ_ASSERT((aSideBits & ~eSideBitsAll) == 0, "illegal side bits");
-    return (mBits & aSideBits) == aSideBits;
-  }
-  Sides operator|(Sides aOther) const
-  {
-    return Sides(SideBits(mBits | aOther.mBits));
-  }
-  Sides operator|(SideBits aSideBits) const
-  {
-    return *this | Sides(aSideBits);
-  }
-  Sides& operator|=(Sides aOther)
-  {
-    mBits |= aOther.mBits;
-    return *this;
-  }
-  Sides& operator|=(SideBits aSideBits)
-  {
-    return *this |= Sides(aSideBits);
-  }
-  bool operator==(Sides aOther) const
-  {
-    return mBits == aOther.mBits;
-  }
-  bool operator!=(Sides aOther) const
-  {
-    return !(*this == aOther);
-  }
-
-private:
-  uint8_t mBits;
-};
-
 namespace gfx {
 
 /**
  * Do not use this class directly. Subclass it, pass that subclass as the
  * Sub parameter, and only use that subclass.
  */
 template <class T, class Sub>
 struct BaseMargin {
-  typedef mozilla::Side SideT; // because we have a method named Side
+  typedef mozilla::css::Side SideT;
 
   // Do not change the layout of these members; the Side() methods below
   // depend on this order.
   T top, right, bottom, left;
 
   // Constructors
   BaseMargin() : top(0), right(0), bottom(0), left(0) {}
   BaseMargin(T aTop, T aRight, T aBottom, T aLeft) :
@@ -91,28 +40,28 @@ struct BaseMargin {
     // This is ugly!
     return *(&top + T(aSide));
   }
   T Side(SideT aSide) const {
     // This is ugly!
     return *(&top + T(aSide));
   }
 
-  void ApplySkipSides(Sides aSkipSides)
+  void ApplySkipSides(int aSkipSides)
   {
-    if (aSkipSides.Top()) {
+    if (aSkipSides & (1 << mozilla::css::eSideTop)) {
       top = 0;
     }
-    if (aSkipSides.Right()) {
+    if (aSkipSides & (1 << mozilla::css::eSideRight)) {
       right = 0;
     }
-    if (aSkipSides.Bottom()) {
+    if (aSkipSides & (1 << mozilla::css::eSideBottom)) {
       bottom = 0;
     }
-    if (aSkipSides.Left()) {
+    if (aSkipSides & (1 << mozilla::css::eSideLeft)) {
       left = 0;
     }
   }
 
   // Overloaded operators. Note that '=' isn't defined so we'll get the
   // compiler generated default assignment operator
   bool operator==(const Sub& aMargin) const {
     return top == aMargin.top && right == aMargin.right &&

--- a/gfx/2d/Types.h
+++ b/gfx/2d/Types.h
@@ -259,30 +259,22 @@ struct GradientStop
 #define GFX2D_API __declspec(dllexport)
 #else
 #define GFX2D_API __declspec(dllimport)
 #endif
 #else
 #define GFX2D_API
 #endif
 
+// Side constants for use in various places
 namespace mozilla {
-// Side constants for use in various places.
-enum Side { eSideTop, eSideRight, eSideBottom, eSideLeft };
+  namespace css {
+    enum Side {eSideTop, eSideRight, eSideBottom, eSideLeft};
+  }
+}
 
-enum SideBits {
-  eSideBitsNone   = 0,
-  eSideBitsTop    = 1 << eSideTop,
-  eSideBitsRight  = 1 << eSideRight,
-  eSideBitsBottom = 1 << eSideBottom,
-  eSideBitsLeft   = 1 << eSideLeft,
-  eSideBitsTopBottom = eSideBitsTop  | eSideBitsBottom,
-  eSideBitsLeftRight = eSideBitsLeft | eSideBitsRight,
-  eSideBitsAll = eSideBitsTopBottom | eSideBitsLeftRight
-};
-} // namespace mozilla
-
-#define NS_SIDE_TOP    mozilla::eSideTop
-#define NS_SIDE_RIGHT  mozilla::eSideRight
-#define NS_SIDE_BOTTOM mozilla::eSideBottom
-#define NS_SIDE_LEFT   mozilla::eSideLeft
+// XXX - These don't really belong here. But for now this is where they go.
+#define NS_SIDE_TOP     mozilla::css::eSideTop
+#define NS_SIDE_RIGHT   mozilla::css::eSideRight
+#define NS_SIDE_BOTTOM  mozilla::css::eSideBottom
+#define NS_SIDE_LEFT    mozilla::css::eSideLeft
 
 #endif /* MOZILLA_GFX_TYPES_H_ */

--- a/gfx/thebes/gfxRect.h
+++ b/gfx/thebes/gfxRect.h
@@ -82,27 +82,27 @@ struct gfxRect :
             case NS_CORNER_BOTTOM_LEFT: return BottomLeft();
             default:
                 NS_ERROR("Invalid corner!");
                 break;
         }
         return gfxPoint(0.0, 0.0);
     }
 
-    gfxPoint CCWCorner(mozilla::Side side) const {
+    gfxPoint CCWCorner(mozilla::css::Side side) const {
         switch (side) {
             case NS_SIDE_TOP: return TopLeft();
             case NS_SIDE_RIGHT: return TopRight();
             case NS_SIDE_BOTTOM: return BottomRight();
             case NS_SIDE_LEFT: return BottomLeft();
         }
         MOZ_CRASH("Incomplete switch");
     }
 
-    gfxPoint CWCorner(mozilla::Side side) const {
+    gfxPoint CWCorner(mozilla::css::Side side) const {
         switch (side) {
             case NS_SIDE_TOP: return TopRight();
             case NS_SIDE_RIGHT: return BottomRight();
             case NS_SIDE_BOTTOM: return BottomLeft();
             case NS_SIDE_LEFT: return TopLeft();
         }
         MOZ_CRASH("Incomplete switch");
     }

--- a/layout/base/nsCSSRendering.cpp
+++ b/layout/base/nsCSSRendering.cpp
@@ -298,17 +298,17 @@ protected:
       NS_ASSERTION(mBlockFrame, "Cannot find containing block.");
     }
 
     // Start with the previous flow frame as our continuation point
     // is the total of the widths of the previous frames.
     nsIFrame* inlineFrame = GetPrevContinuation(aFrame);
     while (inlineFrame) {
       if (!mLeftBorderData.mFrame &&
-          !inlineFrame->GetSkipSides().Left()) {
+          !(inlineFrame->GetSkipSides() & SIDE_BIT_LEFT)) {
         mLeftBorderData.mFrame = inlineFrame;
       }
       nsRect rect = inlineFrame->GetRect();
       mContinuationPoint += rect.width;
       if (mBidiEnabled && !AreOnSameLine(aFrame, inlineFrame)) {
         mLineContinuationPoint += rect.width;
       }
       mUnbrokenWidth += rect.width;
@@ -316,17 +316,17 @@ protected:
       inlineFrame = GetPrevContinuation(inlineFrame);
     }
 
     // Next add this frame and subsequent frames to the bounding box and
     // unbroken width.
     inlineFrame = aFrame;
     while (inlineFrame) {
       if (!mLeftBorderData.mFrame &&
-          !inlineFrame->GetSkipSides().Left()) {
+          !(inlineFrame->GetSkipSides() & SIDE_BIT_LEFT)) {
         mLeftBorderData.mFrame = inlineFrame;
       }
       nsRect rect = inlineFrame->GetRect();
       mUnbrokenWidth += rect.width;
       mBoundingBox.UnionRect(mBoundingBox, rect);
       inlineFrame = GetNextContinuation(inlineFrame);
     }
 
@@ -357,17 +357,17 @@ struct ColorStop {
 
 /* Local functions */
 static void DrawBorderImage(nsPresContext* aPresContext,
                             nsRenderingContext& aRenderingContext,
                             nsIFrame* aForFrame,
                             const nsRect& aBorderArea,
                             const nsStyleBorder& aStyleBorder,
                             const nsRect& aDirtyRect,
-                            Sides aSkipSides);
+                            int aSkipSides);
 
 static nscolor MakeBevelColor(mozilla::css::Side whichSide, uint8_t style,
                               nscolor aBackgroundColor,
                               nscolor aBorderColor);
 
 static InlineBackgroundData* gInlineBGData = nullptr;
 
 // Initialize any static variables used by nsCSSRendering.
@@ -434,20 +434,20 @@ GetRadii(nsIFrame* aForFrame, const nsSt
          gfxCornerSizes* aBgRadii)
 {
   nscoord radii[8];
   bool haveRoundedCorners;
   nsSize sz = aBorderArea.Size();
   nsSize frameSize = aForFrame->GetSize();
   if (&aBorder == aForFrame->StyleBorder() &&
       frameSize == aOrigBorderArea.Size()) {
-    haveRoundedCorners = aForFrame->GetBorderRadii(sz, sz, Sides(), radii);
+    haveRoundedCorners = aForFrame->GetBorderRadii(sz, sz, 0, radii);
    } else {
     haveRoundedCorners =
-      nsIFrame::ComputeBorderRadii(aBorder.mBorderRadius, frameSize, sz, Sides(), radii);
+      nsIFrame::ComputeBorderRadii(aBorder.mBorderRadius, frameSize, sz, 0, radii);
   }
   if (haveRoundedCorners) {
     auto d2a = aForFrame->PresContext()->AppUnitsPerDevPixel();
     nsCSSRendering::ComputePixelRadii(radii, d2a, aBgRadii);
   }
   return haveRoundedCorners;
 }
 
@@ -556,17 +556,17 @@ nsCSSRendering::ComputePixelRadii(const 
 
 void
 nsCSSRendering::PaintBorder(nsPresContext* aPresContext,
                             nsRenderingContext& aRenderingContext,
                             nsIFrame* aForFrame,
                             const nsRect& aDirtyRect,
                             const nsRect& aBorderArea,
                             nsStyleContext* aStyleContext,
-                            Sides aSkipSides)
+                            int aSkipSides)
 {
   PROFILER_LABEL("nsCSSRendering", "PaintBorder",
     js::ProfileEntry::Category::GRAPHICS);
 
   nsStyleContext *styleIfVisited = aStyleContext->GetStyleIfVisited();
   const nsStyleBorder *styleBorder = aStyleContext->StyleBorder();
   // Don't check RelevantLinkVisited here, since we want to take the
   // same amount of time whether or not it's true.
@@ -601,17 +601,17 @@ nsCSSRendering::PaintBorder(nsPresContex
 void
 nsCSSRendering::PaintBorderWithStyleBorder(nsPresContext* aPresContext,
                                            nsRenderingContext& aRenderingContext,
                                            nsIFrame* aForFrame,
                                            const nsRect& aDirtyRect,
                                            const nsRect& aBorderArea,
                                            const nsStyleBorder& aStyleBorder,
                                            nsStyleContext* aStyleContext,
-                                           Sides aSkipSides)
+                                           int aSkipSides)
 {
   SN("++ PaintBorder");
 
   // Check to see if we have an appearance defined.  If so, we let the theme
   // renderer draw the border.  DO not get the data from aForFrame, since the passed in style context
   // may be different!  Always use |aStyleContext|!
   const nsStyleDisplay* displayData = aStyleContext->StyleDisplay();
   if (displayData->mAppearance) {
@@ -655,32 +655,32 @@ nsCSSRendering::PaintBorderWithStyleBord
   SF(" joinedBorderArea: %d %d %d %d\n", joinedBorderArea.x, joinedBorderArea.y,
      joinedBorderArea.width, joinedBorderArea.height);
 
   // start drawing
   gfxContext* ctx = aRenderingContext.ThebesContext();
   ctx->Save();
 
   if (::IsBoxDecorationSlice(aStyleBorder)) {
-    if (aSkipSides.IsEmpty()) {
+    if (aSkipSides == 0) {
       // No continuations most likely, or ::first-letter that wants all border-
       // sides on the first continuation.
       joinedBorderArea = aBorderArea;
     } else if (joinedBorderArea.IsEqualEdges(aBorderArea)) {
       // No need for a clip, just skip the sides we don't want.
       border.ApplySkipSides(aSkipSides);
     } else {
       // We're drawing borders around the joined continuation boxes so we need
       // to clip that to the slice that we want for this frame.
       aRenderingContext.IntersectClip(aBorderArea);
     }
   } else {
     MOZ_ASSERT(joinedBorderArea.IsEqualEdges(aBorderArea),
                "Should use aBorderArea for box-decoration-break:clone");
-    MOZ_ASSERT(aForFrame->GetSkipSides().IsEmpty(),
+    MOZ_ASSERT(aForFrame->GetSkipSides() == 0,
                "Should not skip sides for box-decoration-break:clone except "
                "::first-letter/line continuations or other frame types that "
                "don't have borders but those shouldn't reach this point.");
   }
 
   // Convert to dev pixels.
   nscoord twipsPerPixel = aPresContext->DevPixelsToAppUnits(1);
   gfxRect joinedBorderAreaPx =
@@ -796,17 +796,17 @@ nsCSSRendering::PaintOutline(nsPresConte
   if (innerRect.Contains(aDirtyRect))
     return;
 
   nsRect outerRect = innerRect;
   outerRect.Inflate(width, width);
 
   // get the radius for our outline
   nsIFrame::ComputeBorderRadii(ourOutline->mOutlineRadius, aBorderArea.Size(),
-                               outerRect.Size(), Sides(), twipsRadii);
+                               outerRect.Size(), 0, twipsRadii);
 
   // Get our conversion values
   nscoord twipsPerPixel = aPresContext->DevPixelsToAppUnits(1);
 
   // get the outer rectangles
   gfxRect oRect(nsLayoutUtils::RectToGfxRect(outerRect, twipsPerPixel));
 
   // convert the radii
@@ -1196,17 +1196,17 @@ nsCSSRendering::PaintBoxShadowOuter(nsPr
   // the frame does.
   gfxCornerSizes borderRadii;
   const nscoord twipsPerPixel = aPresContext->DevPixelsToAppUnits(1);
   if (hasBorderRadius) {
     nscoord twipsRadii[8];
     NS_ASSERTION(aFrameArea.Size() == aForFrame->VisualBorderRectRelativeToSelf().Size(),
                  "unexpected size");
     nsSize sz = frameRect.Size();
-    hasBorderRadius = aForFrame->GetBorderRadii(sz, sz, Sides(), twipsRadii);
+    hasBorderRadius = aForFrame->GetBorderRadii(sz, sz, 0, twipsRadii);
     if (hasBorderRadius) {
       ComputePixelRadii(twipsRadii, twipsPerPixel, &borderRadii);
     }
   }
 
   gfxRect frameGfxRect(nsLayoutUtils::RectToGfxRect(frameRect, twipsPerPixel));
   frameGfxRect.Round();
 
@@ -1225,17 +1225,17 @@ nsCSSRendering::PaintBoxShadowOuter(nsPr
       aForFrame->GetPaddingRect() - aForFrame->GetPosition() + aFrameArea.TopLeft();
     skipGfxRect = nsLayoutUtils::RectToGfxRect(paddingRect, twipsPerPixel);
   } else if (hasBorderRadius) {
     skipGfxRect.Deflate(gfxMargin(
         std::max(borderRadii[C_TL].height, borderRadii[C_TR].height), 0,
         std::max(borderRadii[C_BL].height, borderRadii[C_BR].height), 0));
   }
 
-  Sides skipSides = aForFrame->GetSkipSides();
+  int skipSides = aForFrame->GetSkipSides();
   for (uint32_t i = shadows->Length(); i > 0; --i) {
     nsCSSShadowItem* shadowItem = shadows->ShadowAt(i - 1);
     if (shadowItem->mInset)
       continue;
 
     nsRect shadowRect = frameRect;
     shadowRect.MoveBy(shadowItem->mXOffset, shadowItem->mYOffset);
     if (!nativeTheme) {
@@ -1320,35 +1320,35 @@ nsCSSRendering::PaintBoxShadowOuter(nsPr
         renderContext->Rectangle(frameGfxRect);
       }
 
       renderContext->SetFillRule(gfxContext::FILL_RULE_EVEN_ODD);
       renderContext->Clip();
 
       // Clip the shadow so that we only get the part that applies to aForFrame.
       nsRect fragmentClip = shadowRectPlusBlur;
-      if (!skipSides.IsEmpty()) {
-        if (skipSides.Left()) {
+      if (skipSides) {
+        if (skipSides & SIDE_BIT_LEFT) {
           nscoord xmost = fragmentClip.XMost();
           fragmentClip.x = aFrameArea.x;
           fragmentClip.width = xmost - fragmentClip.x;
         }
-        if (skipSides.Right()) {
+        if (skipSides & SIDE_BIT_RIGHT) {
           nscoord xmost = fragmentClip.XMost();
           nscoord overflow = xmost - aFrameArea.XMost();
           if (overflow > 0) {
             fragmentClip.width -= overflow;
           }
         }
-        if (skipSides.Top()) {
+        if (skipSides & SIDE_BIT_TOP) {
           nscoord ymost = fragmentClip.YMost();
           fragmentClip.y = aFrameArea.y;
           fragmentClip.height = ymost - fragmentClip.y;
         }
-        if (skipSides.Bottom()) {
+        if (skipSides & SIDE_BIT_BOTTOM) {
           nscoord ymost = fragmentClip.YMost();
           nscoord overflow = ymost - aFrameArea.YMost();
           if (overflow > 0) {
             fragmentClip.height -= overflow;
           }
         }
       }
       aRenderingContext.IntersectClip(fragmentClip);
@@ -1409,17 +1409,17 @@ nsCSSRendering::PaintBoxShadowInner(nsPr
   nsRect paddingRect = frameRect;
   nsMargin border = aForFrame->GetUsedBorder();
   paddingRect.Deflate(border);
 
   // Get any border radius, since box-shadow must also have rounded corners
   // if the frame does.
   nscoord twipsRadii[8];
   nsSize sz = frameRect.Size();
-  bool hasBorderRadius = aForFrame->GetBorderRadii(sz, sz, Sides(), twipsRadii);
+  bool hasBorderRadius = aForFrame->GetBorderRadii(sz, sz, 0, twipsRadii);
   const nscoord twipsPerPixel = aPresContext->DevPixelsToAppUnits(1);
 
   gfxCornerSizes innerRadii;
   if (hasBorderRadius) {
     gfxCornerSizes borderRadii;
 
     ComputePixelRadii(twipsRadii, twipsPerPixel, &borderRadii);
     gfxFloat borderSizes[4] = {
@@ -3291,17 +3291,17 @@ nsCSSRendering::AreAllBackgroundImagesDe
 
 static void
 DrawBorderImage(nsPresContext*       aPresContext,
                 nsRenderingContext&  aRenderingContext,
                 nsIFrame*            aForFrame,
                 const nsRect&        aBorderArea,
                 const nsStyleBorder& aStyleBorder,
                 const nsRect&        aDirtyRect,
-                Sides                aSkipSides)
+                int                  aSkipSides)
 {
   NS_PRECONDITION(aStyleBorder.IsBorderImageLoaded(),
                   "drawing border image that isn't successfully loaded");
 
   if (aDirtyRect.IsEmpty())
     return;
 
   nsImageRenderer renderer(aForFrame, &aStyleBorder.mBorderImageSource, 0);
@@ -3324,17 +3324,17 @@ DrawBorderImage(nsPresContext*       aPr
 
   // Determine the border image area, which by default corresponds to the
   // border box but can be modified by 'border-image-outset'.
   // Note that 'border-radius' do not apply to 'border-image' borders per
   // <http://dev.w3.org/csswg/css-backgrounds/#corner-clipping>.
   nsRect borderImgArea;
   nsMargin borderWidths(aStyleBorder.GetComputedBorder());
   nsMargin imageOutset(aStyleBorder.GetImageOutset());
-  if (::IsBoxDecorationSlice(aStyleBorder) && !aSkipSides.IsEmpty()) {
+  if (::IsBoxDecorationSlice(aStyleBorder) && aSkipSides != 0) {
     borderImgArea =
       ::BoxDecorationRectForBorder(aForFrame, aBorderArea, &aStyleBorder);
     if (borderImgArea.IsEqualEdges(aBorderArea)) {
       // No need for a clip, just skip the sides we don't want.
       borderWidths.ApplySkipSides(aSkipSides);
       imageOutset.ApplySkipSides(aSkipSides);
       borderImgArea.Inflate(imageOutset);
     } else {

--- a/layout/base/nsCSSRendering.h
+++ b/layout/base/nsCSSRendering.h
@@ -274,18 +274,16 @@ struct nsBackgroundLayerState {
   nsPoint mAnchor;
   /**
    * The compositing operation that the image should use
    */
   gfxContext::GraphicsOperator mCompositingOp;
 };
 
 struct nsCSSRendering {
-  typedef nsIFrame::Sides Sides;
-
   /**
    * Initialize any static variables used by nsCSSRendering.
    */
   static void Init();
   
   /**
    * Clean up any static variables used by nsCSSRendering.
    */
@@ -305,45 +303,45 @@ struct nsCSSRendering {
                                   float aOpacity = 1.0);
 
   static void ComputePixelRadii(const nscoord *aAppUnitsRadii,
                                 nscoord aAppUnitsPerPixel,
                                 gfxCornerSizes *oBorderRadii);
 
   /**
    * Render the border for an element using css rendering rules
-   * for borders. aSkipSides says which sides to skip
-   * when rendering, the default is to skip none.
+   * for borders. aSkipSides is a bitmask of the sides to skip
+   * when rendering. If 0 then no sides are skipped.
    */
   static void PaintBorder(nsPresContext* aPresContext,
                           nsRenderingContext& aRenderingContext,
                           nsIFrame* aForFrame,
                           const nsRect& aDirtyRect,
                           const nsRect& aBorderArea,
                           nsStyleContext* aStyleContext,
-                          Sides aSkipSides = Sides());
+                          int aSkipSides = 0);
 
   /**
    * Like PaintBorder, but taking an nsStyleBorder argument instead of
-   * getting it from aStyleContext. aSkipSides says which sides to skip
-   * when rendering, the default is to skip none.
+   * getting it from aStyleContext.
    */
   static void PaintBorderWithStyleBorder(nsPresContext* aPresContext,
                                          nsRenderingContext& aRenderingContext,
                                          nsIFrame* aForFrame,
                                          const nsRect& aDirtyRect,
                                          const nsRect& aBorderArea,
                                          const nsStyleBorder& aBorderStyle,
                                          nsStyleContext* aStyleContext,
-                                         Sides aSkipSides = Sides());
+                                         int aSkipSides = 0);
 
 
   /**
    * Render the outline for an element using css rendering rules
-   * for borders.
+   * for borders. aSkipSides is a bitmask of the sides to skip
+   * when rendering. If 0 then no sides are skipped.
    */
   static void PaintOutline(nsPresContext* aPresContext,
                           nsRenderingContext& aRenderingContext,
                           nsIFrame* aForFrame,
                           const nsRect& aDirtyRect,
                           const nsRect& aBorderArea,
                           nsStyleContext* aStyleContext);
 

--- a/layout/generic/StickyScrollContainer.cpp
+++ b/layout/generic/StickyScrollContainer.cpp
@@ -10,16 +10,18 @@
  */
 
 #include "StickyScrollContainer.h"
 #include "nsIFrame.h"
 #include "nsIScrollableFrame.h"
 #include "nsLayoutUtils.h"
 #include "RestyleTracker.h"
 
+using namespace mozilla::css;
+
 namespace mozilla {
 
 void DestroyStickyScrollContainer(void* aPropertyValue)
 {
   delete static_cast<StickyScrollContainer*>(aPropertyValue);
 }
 
 NS_DECLARE_FRAME_PROPERTY(StickyScrollContainerProperty,

--- a/layout/generic/WritingModes.h
+++ b/layout/generic/WritingModes.h
@@ -31,94 +31,40 @@
 // the writing modes match.
 // (In some cases, there are internal (private) methods that don't do this;
 // such methods should only be used by other methods that have already checked
 // the writing modes.)
 
 #define CHECK_WRITING_MODE(param) \
    NS_ASSERTION(param == mWritingMode, "writing-mode mismatch")
 
-namespace mozilla {
-// Logical side constants for use in various places.
-enum LogicalSide { eLogicalSideBStart, eLogicalSideBEnd,
-                   eLogicalSideIStart, eLogicalSideIEnd };
-
-enum LogicalSideBits {
-  eLogicalSideBitsNone   = 0,
-  eLogicalSideBitsBStart = 1 << eLogicalSideBStart,
-  eLogicalSideBitsBEnd   = 1 << eLogicalSideBEnd,
-  eLogicalSideBitsIEnd   = 1 << eLogicalSideIEnd,
-  eLogicalSideBitsIStart = 1 << eLogicalSideIStart,
-  eLogicalSideBitsBBoth = eLogicalSideBitsBStart | eLogicalSideBitsBEnd,
-  eLogicalSideBitsIBoth = eLogicalSideBitsIStart | eLogicalSideBitsIEnd,
-  eLogicalSideBitsAll = eLogicalSideBitsBBoth | eLogicalSideBitsIBoth
-};
-
-/**
- * LogicalSides represents a set of logical sides.
- */
-struct LogicalSides MOZ_FINAL {
-  LogicalSides() : mBits(0) {}
-  explicit LogicalSides(LogicalSideBits aSideBits)
-  {
-    MOZ_ASSERT((aSideBits & ~eLogicalSideBitsAll) == 0, "illegal side bits");
-    mBits = aSideBits;
-  }
-  bool IsEmpty() const { return mBits == 0; }
-  bool BStart()  const { return mBits & eLogicalSideBitsBStart; }
-  bool BEnd()    const { return mBits & eLogicalSideBitsBEnd; }
-  bool IStart()  const { return mBits & eLogicalSideBitsIStart; }
-  bool IEnd()    const { return mBits & eLogicalSideBitsIEnd; }
-  bool Contains(LogicalSideBits aSideBits) const
-  {
-    MOZ_ASSERT((aSideBits & ~eLogicalSideBitsAll) == 0, "illegal side bits");
-    return (mBits & aSideBits) == aSideBits;
-  }
-  LogicalSides operator|(LogicalSides aOther) const
-  {
-    return LogicalSides(LogicalSideBits(mBits | aOther.mBits));
-  }
-  LogicalSides operator|(LogicalSideBits aSideBits) const
-  {
-    return *this | LogicalSides(aSideBits);
-  }
-  LogicalSides& operator|=(LogicalSides aOther)
-  {
-    mBits |= aOther.mBits;
-    return *this;
-  }
-  LogicalSides& operator|=(LogicalSideBits aSideBits)
-  {
-    return *this |= LogicalSides(aSideBits);
-  }
-  bool operator==(LogicalSides aOther) const
-  {
-    return mBits == aOther.mBits;
-  }
-  bool operator!=(LogicalSides aOther) const
-  {
-    return !(*this == aOther);
-  }
-
-private:
-  uint8_t mBits;
-};
+#define LOGICAL_SIDE_B_START 1
+#define LOGICAL_SIDE_I_START 2
+#define LOGICAL_SIDE_B_END   4
+#define LOGICAL_SIDE_I_END   8
+#define LOGICAL_SIDES_I_BOTH (LOGICAL_SIDE_I_START | LOGICAL_SIDE_I_END)
+#define LOGICAL_SIDES_B_BOTH (LOGICAL_SIDE_B_START | LOGICAL_SIDE_B_END)
+#define LOGICAL_SIDES_ALL (LOGICAL_SIDE_I_START | LOGICAL_SIDE_I_END | \
+                           LOGICAL_SIDE_B_START | LOGICAL_SIDE_B_END)
 
 /**
  * mozilla::WritingMode is an immutable class representing a
  * writing mode.
  *
  * It efficiently stores the writing mode and can rapidly compute
  * interesting things about it for use in layout.
  *
  * Writing modes are computed from the CSS 'direction',
  * 'writing-mode', and 'text-orientation' properties.
  * See CSS3 Writing Modes for more information
  *   http://www.w3.org/TR/css3-writing-modes/
  */
+
+namespace mozilla {
+
 class WritingMode {
 public:
   /**
    * Absolute inline flow direction
    */
   enum InlineDir {
     eInlineLTR = 0x00, // text flows horizontally left to right
     eInlineRTL = 0x02, // text flows horizontally right to left
@@ -891,28 +837,28 @@ public:
    */
   LogicalMargin ConvertTo(WritingMode aToMode, WritingMode aFromMode) const
   {
     CHECK_WRITING_MODE(aFromMode);
     return aToMode == aFromMode ?
       *this : LogicalMargin(aToMode, GetPhysicalMargin(aFromMode));
   }
 
-  void ApplySkipSides(LogicalSides aSkipSides)
+  void ApplySkipSides(int aSkipSides)
   {
-    if (aSkipSides.BStart()) {
+    if (aSkipSides & LOGICAL_SIDE_B_START) {
       BStart() = 0;
     }
-    if (aSkipSides.BEnd()) {
+    if (aSkipSides & LOGICAL_SIDE_B_END) {
       BEnd() = 0;
     }
-    if (aSkipSides.IStart()) {
+    if (aSkipSides & LOGICAL_SIDE_I_START) {
       IStart() = 0;
     }
-    if (aSkipSides.IEnd()) {
+    if (aSkipSides & LOGICAL_SIDE_I_END) {
       IEnd() = 0;
     }
   }
 
   bool IsEmpty() const
   {
     return (mMargin.left == 0 && mMargin.top == 0 &&
             mMargin.right == 0 && mMargin.bottom == 0);

--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@@ -1033,17 +1033,17 @@ nsBlockFrame::Reflow(nsPresContext*     
                                                              consumedBSize);
   Maybe<nsHTMLReflowState> mutableReflowState;
   // If we have non-auto block size, we're clipping our kids and we fit,
   // make sure our kids fit too.
   if (aReflowState.AvailableBSize() != NS_UNCONSTRAINEDSIZE &&
       aReflowState.ComputedBSize() != NS_AUTOHEIGHT &&
       ShouldApplyOverflowClipping(this, aReflowState.mStyleDisplay)) {
     LogicalMargin blockDirExtras = aReflowState.ComputedLogicalBorderPadding();
-    if (GetLogicalSkipSides().BStart()) {
+    if (GetLogicalSkipSides() & (LOGICAL_SIDE_B_START)) {
       blockDirExtras.BStart(wm) = 0;
     } else {
       // Bottom margin never causes us to create continuations, so we
       // don't need to worry about whether it fits in its entirety.
       blockDirExtras.BStart(wm) +=
         aReflowState.ComputedLogicalMargin().BStart(wm);
     }
 

--- a/layout/generic/nsBlockReflowState.cpp
+++ b/layout/generic/nsBlockReflowState.cpp
@@ -43,29 +43,28 @@ nsBlockReflowState::nsBlockReflowState(c
     mFlags(0),
     mFloatBreakType(NS_STYLE_CLEAR_NONE),
     mConsumedBSize(aConsumedBSize)
 {
   WritingMode wm = aReflowState.GetWritingMode();
   SetFlag(BRS_ISFIRSTINFLOW, aFrame->GetPrevInFlow() == nullptr);
   SetFlag(BRS_ISOVERFLOWCONTAINER, IS_TRUE_OVERFLOW_CONTAINER(aFrame));
 
-  nsIFrame::LogicalSides logicalSkipSides =
-    aFrame->GetLogicalSkipSides(&aReflowState);
+  int logicalSkipSides = aFrame->GetLogicalSkipSides(&aReflowState);
   mBorderPadding.ApplySkipSides(logicalSkipSides);
 
   // Note that mContainerWidth is the physical width!
   mContainerWidth = aReflowState.ComputedWidth() + mBorderPadding.LeftRight(wm);
 
-  if ((aBStartMarginRoot && !logicalSkipSides.BStart()) ||
+  if ((aBStartMarginRoot && !(logicalSkipSides & LOGICAL_SIDE_B_START)) ||
       0 != mBorderPadding.BStart(wm)) {
     SetFlag(BRS_ISBSTARTMARGINROOT, true);
     SetFlag(BRS_APPLYBSTARTMARGIN, true);
   }
-  if ((aBEndMarginRoot && !logicalSkipSides.BEnd()) ||
+  if ((aBEndMarginRoot && !(logicalSkipSides & LOGICAL_SIDE_B_END)) ||
       0 != mBorderPadding.BEnd(wm)) {
     SetFlag(BRS_ISBENDMARGINROOT, true);
   }
   if (aBlockNeedsFloatManager) {
     SetFlag(BRS_FLOAT_MGR, true);
   }
   
   mFloatManager = aReflowState.mFloatManager;

--- a/layout/generic/nsColumnSetFrame.cpp
+++ b/layout/generic/nsColumnSetFrame.cpp
@@ -105,22 +105,20 @@ nsColumnSetFrame::PaintColumnRule(nsRend
     // Each child frame's position coordinates is actually relative to this nsColumnSetFrame.
     // linePt will be at the top-left edge to paint the line.
     nsPoint edgeOfLeftSibling = leftSibling->GetRect().TopRight() + aPt;
     nsPoint edgeOfRightSibling = rightSibling->GetRect().TopLeft() + aPt;
     nsPoint linePt((edgeOfLeftSibling.x + edgeOfRightSibling.x - ruleWidth) / 2,
                    contentRect.y);
 
     nsRect lineRect(linePt, ruleSize);
-    // Remember, we only have the "left" "border". Skip everything else.
-    Sides skipSides(mozilla::eSideBitsTopBottom);
-    skipSides |= mozilla::eSideBitsRight;
     nsCSSRendering::PaintBorderWithStyleBorder(presContext, *aCtx, this,
         aDirtyRect, lineRect, border, StyleContext(),
-        skipSides);
+        // Remember, we only have the "left" "border". Skip everything else
+        (1 << NS_SIDE_TOP | 1 << NS_SIDE_RIGHT | 1 << NS_SIDE_BOTTOM));
 
     child = nextSibling;
     nextSibling = nextSibling->GetNextSibling();
   }
 }
 
 static nscoord
 GetAvailableContentWidth(const nsHTMLReflowState& aReflowState)

--- a/layout/generic/nsFirstLetterFrame.cpp
+++ b/layout/generic/nsFirstLetterFrame.cpp
@@ -373,21 +373,21 @@ nsFirstLetterFrame::DrainOverflowFrames(
 }
 
 nscoord
 nsFirstLetterFrame::GetLogicalBaseline(WritingMode aWritingMode) const
 {
   return mBaseline;
 }
 
-nsIFrame::LogicalSides
+int
 nsFirstLetterFrame::GetLogicalSkipSides(const nsHTMLReflowState* aReflowState) const
 {
   if (GetPrevContinuation()) {
     // We shouldn't get calls to GetSkipSides for later continuations since
     // they have separate style contexts with initial values for all the
     // properties that could trigger a call to GetSkipSides.  Then again,
     // it's not really an error to call GetSkipSides on any frame, so
     // that's why we handle it properly.
-    return LogicalSides(eLogicalSideBitsAll);
+    return LOGICAL_SIDES_ALL;
   }
-  return LogicalSides();  // first continuation displays all sides
+  return 0;  // first continuation displays all sides
 }

--- a/layout/generic/nsFirstLetterFrame.h
+++ b/layout/generic/nsFirstLetterFrame.h
@@ -55,17 +55,17 @@ public:
                              uint32_t aFlags) MOZ_OVERRIDE;
   virtual void Reflow(nsPresContext*           aPresContext,
                       nsHTMLReflowMetrics&     aDesiredSize,
                       const nsHTMLReflowState& aReflowState,
                       nsReflowStatus&          aStatus) MOZ_OVERRIDE;
 
   virtual bool CanContinueTextRun() const MOZ_OVERRIDE;
   virtual nscoord GetLogicalBaseline(mozilla::WritingMode aWritingMode) const MOZ_OVERRIDE;
-  virtual LogicalSides GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
+  virtual int GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
 
 //override of nsFrame method
   virtual nsresult GetChildFrameContainingOffset(int32_t inContentOffset,
                                                  bool inHint,
                                                  int32_t* outFrameContentOffset,
                                                  nsIFrame** outChildFrame) MOZ_OVERRIDE;
 
   nscoord GetFirstLetterBaseline() const { return mBaseline; }

--- a/layout/generic/nsFlexContainerFrame.cpp
+++ b/layout/generic/nsFlexContainerFrame.cpp
@@ -16,16 +16,17 @@
 #include "nsPlaceholderFrame.h"
 #include "nsPresContext.h"
 #include "nsStyleContext.h"
 #include "prlog.h"
 #include <algorithm>
 #include "mozilla/LinkedList.h"
 
 using namespace mozilla;
+using namespace mozilla::css;
 using namespace mozilla::layout;
 
 // Convenience typedefs for helper classes that we forward-declare in .h file
 // (so that nsFlexContainerFrame methods can use them as parameters):
 typedef nsFlexContainerFrame::FlexItem FlexItem;
 typedef nsFlexContainerFrame::FlexLine FlexLine;
 typedef nsFlexContainerFrame::FlexboxAxisTracker FlexboxAxisTracker;
 typedef nsFlexContainerFrame::StrutInfo StrutInfo;
@@ -68,18 +69,18 @@ enum AxisOrientationType {
 // the sub-arrays in 'kAxisOrientationToSidesMap', defined below.
 enum AxisEdgeType {
   eAxisEdge_Start,
   eAxisEdge_End,
   eNumAxisEdges // For sizing arrays that use these values as indices
 };
 
 // This array maps each axis orientation to a pair of corresponding
-// [start, end] physical mozilla::Side values.
-static const mozilla::Side
+// [start, end] physical mozilla::css::Side values.
+static const Side
 kAxisOrientationToSidesMap[eNumAxisOrientationTypes][eNumAxisEdges] = {
   { eSideLeft,   eSideRight  },  // eAxis_LR
   { eSideRight,  eSideLeft   },  // eAxis_RL
   { eSideTop,    eSideBottom },  // eAxis_TB
   { eSideBottom, eSideTop }      // eAxis_BT
 };
 
 // Helper structs / classes / methods
@@ -149,17 +150,17 @@ PhysicalPosFromLogicalPos(nscoord aLogic
                           AxisOrientationType aAxis) {
   if (AxisGrowsInPositiveDirection(aAxis)) {
     return aLogicalPosn;
   }
   return aLogicalContainerSize - aLogicalPosn;
 }
 
 static nscoord
-MarginComponentForSide(const nsMargin& aMargin, mozilla::Side aSide)
+MarginComponentForSide(const nsMargin& aMargin, Side aSide)
 {
   switch (aSide) {
     case eSideLeft:
       return aMargin.left;
     case eSideRight:
       return aMargin.right;
     case eSideTop:
       return aMargin.top;
@@ -168,17 +169,17 @@ MarginComponentForSide(const nsMargin& a
   }
 
   NS_NOTREACHED("unexpected Side enum");
   return aMargin.left; // have to return something
                        // (but something's busted if we got here)
 }
 
 static nscoord&
-MarginComponentForSide(nsMargin& aMargin, mozilla::Side aSide)
+MarginComponentForSide(nsMargin& aMargin, Side aSide)
 {
   switch (aSide) {
     case eSideLeft:
       return aMargin.left;
     case eSideRight:
       return aMargin.right;
     case eSideTop:
       return aMargin.top;
@@ -409,43 +410,43 @@ public:
     }
     return mFlexShrink * mFlexBaseSize;
   }
 
   // Getters for margin:
   // ===================
   const nsMargin& GetMargin() const { return mMargin; }
 
-  // Returns the margin component for a given mozilla::Side
-  nscoord GetMarginComponentForSide(mozilla::Side aSide) const
+  // Returns the margin component for a given mozilla::css::Side
+  nscoord GetMarginComponentForSide(Side aSide) const
   { return MarginComponentForSide(mMargin, aSide); }
 
   // Returns the total space occupied by this item's margins in the given axis
   nscoord GetMarginSizeInAxis(AxisOrientationType aAxis) const
   {
-    mozilla::Side startSide = kAxisOrientationToSidesMap[aAxis][eAxisEdge_Start];
-    mozilla::Side endSide = kAxisOrientationToSidesMap[aAxis][eAxisEdge_End];
+    Side startSide = kAxisOrientationToSidesMap[aAxis][eAxisEdge_Start];
+    Side endSide = kAxisOrientationToSidesMap[aAxis][eAxisEdge_End];
     return GetMarginComponentForSide(startSide) +
       GetMarginComponentForSide(endSide);
   }
 
   // Getters for border/padding
   // ==========================
   const nsMargin& GetBorderPadding() const { return mBorderPadding; }
 
-  // Returns the border+padding component for a given mozilla::Side
-  nscoord GetBorderPaddingComponentForSide(mozilla::Side aSide) const
+  // Returns the border+padding component for a given mozilla::css::Side
+  nscoord GetBorderPaddingComponentForSide(Side aSide) const
   { return MarginComponentForSide(mBorderPadding, aSide); }
 
   // Returns the total space occupied by this item's borders and padding in
   // the given axis
   nscoord GetBorderPaddingSizeInAxis(AxisOrientationType aAxis) const
   {
-    mozilla::Side startSide = kAxisOrientationToSidesMap[aAxis][eAxisEdge_Start];
-    mozilla::Side endSide = kAxisOrientationToSidesMap[aAxis][eAxisEdge_End];
+    Side startSide = kAxisOrientationToSidesMap[aAxis][eAxisEdge_Start];
+    Side endSide = kAxisOrientationToSidesMap[aAxis][eAxisEdge_End];
     return GetBorderPaddingComponentForSide(startSide) +
       GetBorderPaddingComponentForSide(endSide);
   }
 
   // Getter for combined margin/border/padding
   // =========================================
   // Returns the total space occupied by this item's margins, borders and
   // padding in the given axis
@@ -545,17 +546,17 @@ public:
   }
 
   void SetIsStretched() {
     MOZ_ASSERT(mIsFrozen, "main size should be resolved before this");
     mIsStretched = true;
   }
 
   // Setter for margin components (for resolving "auto" margins)
-  void SetMarginComponentForSide(mozilla::Side aSide, nscoord aLength)
+  void SetMarginComponentForSide(Side aSide, nscoord aLength)
   {
     MOZ_ASSERT(mIsFrozen, "main size should be resolved before this");
     MarginComponentForSide(mMargin, aSide) = aLength;
   }
 
   void ResolveStretchedCrossSize(nscoord aLineCrossSize,
                                  const FlexboxAxisTracker& aAxisTracker);
 
@@ -1267,17 +1268,17 @@ FlexItem::GetBaselineOffsetFromOuterCros
   // measurement -- it's the distance from the border-top edge of this FlexItem
   // to its baseline. So, we can really only do baseline alignment when the
   // cross axis is vertical. (The FlexItem constructor enforces this when
   // resolving the item's "mAlignSelf" value).
   MOZ_ASSERT(!IsAxisHorizontal(aCrossAxis),
              "Only expecting to be doing baseline computations when the "
              "cross axis is vertical");
 
-  mozilla::Side sideToMeasureFrom = kAxisOrientationToSidesMap[aCrossAxis][aEdge];
+  Side sideToMeasureFrom = kAxisOrientationToSidesMap[aCrossAxis][aEdge];
 
   nscoord marginTopToBaseline = mAscent + mMargin.top;
 
   if (sideToMeasureFrom == eSideTop) {
     // Measuring from top (normal case): the distance from the margin-box top
     // edge to the baseline is just ascent + margin-top.
     return marginTopToBaseline;
   }
@@ -1293,17 +1294,17 @@ FlexItem::GetBaselineOffsetFromOuterCros
 }
 
 uint32_t
 FlexItem::GetNumAutoMarginsInAxis(AxisOrientationType aAxis) const
 {
   uint32_t numAutoMargins = 0;
   const nsStyleSides& styleMargin = mFrame->StyleMargin()->mMargin;
   for (uint32_t i = 0; i < eNumAxisEdges; i++) {
-    mozilla::Side side = kAxisOrientationToSidesMap[aAxis][i];
+    Side side = kAxisOrientationToSidesMap[aAxis][i];
     if (styleMargin.GetUnit(side) == eStyleUnit_Auto) {
       numAutoMargins++;
     }
   }
 
   // Mostly for clarity:
   MOZ_ASSERT(numAutoMargins <= 2,
              "We're just looking at one item along one dimension, so we "
@@ -1321,25 +1322,25 @@ public:
   // Accessor for the current value of the position that we're tracking.
   inline nscoord GetPosition() const { return mPosition; }
   inline AxisOrientationType GetAxis() const { return mAxis; }
 
   // Advances our position across the start edge of the given margin, in the
   // axis we're tracking.
   void EnterMargin(const nsMargin& aMargin)
   {
-    mozilla::Side side = kAxisOrientationToSidesMap[mAxis][eAxisEdge_Start];
+    Side side = kAxisOrientationToSidesMap[mAxis][eAxisEdge_Start];
     mPosition += MarginComponentForSide(aMargin, side);
   }
 
   // Advances our position across the end edge of the given margin, in the axis
   // we're tracking.
   void ExitMargin(const nsMargin& aMargin)
   {
-    mozilla::Side side = kAxisOrientationToSidesMap[mAxis][eAxisEdge_End];
+    Side side = kAxisOrientationToSidesMap[mAxis][eAxisEdge_End];
     mPosition += MarginComponentForSide(aMargin, side);
   }
 
   // Advances our current position from the start side of a child frame's
   // border-box to the frame's upper or left edge (depending on our axis).
   // (Note that this is a no-op if our axis grows in positive direction.)
   void EnterChildFrame(nscoord aChildFrameSize)
   {
@@ -2087,17 +2088,17 @@ MainAxisPositionTracker::
 }
 
 void
 MainAxisPositionTracker::ResolveAutoMarginsInMainAxis(FlexItem& aItem)
 {
   if (mNumAutoMarginsInMainAxis) {
     const nsStyleSides& styleMargin = aItem.Frame()->StyleMargin()->mMargin;
     for (uint32_t i = 0; i < eNumAxisEdges; i++) {
-      mozilla::Side side = kAxisOrientationToSidesMap[mAxis][i];
+      Side side = kAxisOrientationToSidesMap[mAxis][i];
       if (styleMargin.GetUnit(side) == eStyleUnit_Auto) {
         // NOTE: This integer math will skew the distribution of remainder
         // app-units towards the end, which is fine.
         nscoord curAutoMarginSize =
           mPackingSpaceRemaining / mNumAutoMarginsInMainAxis;
 
         MOZ_ASSERT(aItem.GetMarginComponentForSide(side) == 0,
                    "Expecting auto margins to have value '0' before we "
@@ -2423,17 +2424,17 @@ SingleLineCrossAxisPositionTracker::
   if (numAutoMargins == 0) {
     return; // No auto margins --> nothing to do.
   }
 
   // OK, we have at least one auto margin and we have some available space.
   // Give each auto margin a share of the space.
   const nsStyleSides& styleMargin = aItem.Frame()->StyleMargin()->mMargin;
   for (uint32_t i = 0; i < eNumAxisEdges; i++) {
-    mozilla::Side side = kAxisOrientationToSidesMap[mAxis][i];
+    Side side = kAxisOrientationToSidesMap[mAxis][i];
     if (styleMargin.GetUnit(side) == eStyleUnit_Auto) {
       MOZ_ASSERT(aItem.GetMarginComponentForSide(side) == 0,
                  "Expecting auto margins to have value '0' before we "
                  "update them");
 
       // NOTE: integer divison is fine here; numAutoMargins is either 1 or 2.
       // If it's 2 & spaceForAutoMargins is odd, 1st margin gets smaller half.
       nscoord curAutoMarginSize = spaceForAutoMargins / numAutoMargins;
@@ -3107,17 +3108,17 @@ nsFlexContainerFrame::Reflow(nsPresConte
   const FlexboxAxisTracker axisTracker(this);
 
   // If we're being fragmented into a constrained height, subtract off
   // borderpadding-top from it, to get the available height for our
   // content box. (Don't subtract if we're skipping top border/padding,
   // though.)
   nscoord availableHeightForContent = aReflowState.AvailableHeight();
   if (availableHeightForContent != NS_UNCONSTRAINEDSIZE &&
-      !GetSkipSides().Top()) {
+      !(GetSkipSides() & (1 << NS_SIDE_TOP))) {
     availableHeightForContent -= aReflowState.ComputedPhysicalBorderPadding().top;
     // (Don't let that push availableHeightForContent below zero, though):
     availableHeightForContent = std::max(availableHeightForContent, 0);
   }
 
   nscoord contentBoxMainSize = GetMainSizeFromReflowState(aReflowState,
                                                           axisTracker);
 

--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -947,61 +947,62 @@ nsIFrame::GetUsedPadding() const
     padding = *p;
   } else {
     DebugOnly<bool> hasPadding = StylePadding()->GetPadding(padding);
     NS_ASSERTION(hasPadding, "We should have padding here! (out of memory?)");
   }
   return padding;
 }
 
-nsIFrame::Sides
+int
 nsIFrame::GetSkipSides(const nsHTMLReflowState* aReflowState) const
 {
   if (MOZ_UNLIKELY(StyleBorder()->mBoxDecorationBreak ==
                      NS_STYLE_BOX_DECORATION_BREAK_CLONE)) {
-    return Sides();
+    return 0;
   }
 
   // Convert the logical skip sides to physical sides using the frame's
   // writing mode
   WritingMode writingMode = GetWritingMode();
-  LogicalSides logicalSkip = GetLogicalSkipSides(aReflowState);
-  Sides skip;
-
-  if (logicalSkip.BStart()) {
+  int logicalSkip = GetLogicalSkipSides(aReflowState);
+  int skip = 0;
+
+  if (logicalSkip & LOGICAL_SIDE_B_START) {
     if (writingMode.IsVertical()) {
-      skip |= writingMode.IsVerticalLR() ? eSideBitsLeft : eSideBitsRight;
+      skip |= 1 << (writingMode.IsVerticalLR() ? NS_SIDE_LEFT : NS_SIDE_RIGHT);
     } else {
-      skip |= eSideBitsTop;
-    }
-  }
-
-  if (logicalSkip.BEnd()) {
+      skip |= 1 << NS_SIDE_TOP;
+    }
+  }
+
+  if (logicalSkip & LOGICAL_SIDE_B_END) {
     if (writingMode.IsVertical()) {
-      skip |= writingMode.IsVerticalLR() ? eSideBitsRight : eSideBitsLeft;
+      skip |= 1 << (writingMode.IsVerticalLR() ? NS_SIDE_RIGHT : NS_SIDE_LEFT);
     } else {
-      skip |= eSideBitsBottom;
-    }
-  }
-
-  if (logicalSkip.IStart()) {
+      skip |= 1 << NS_SIDE_BOTTOM;
+    }
+  }
+
+  if (logicalSkip & LOGICAL_SIDE_I_START) {
     if (writingMode.IsVertical()) {
-      skip |= eSideBitsTop;
+      skip |= 1 << NS_SIDE_TOP;
     } else {
-      skip |= writingMode.IsBidiLTR() ? eSideBitsLeft : eSideBitsRight;
-    }
-  }
-
-  if (logicalSkip.IEnd()) {
+      skip |= 1 << (writingMode.IsBidiLTR() ? NS_SIDE_LEFT : NS_SIDE_RIGHT);
+    }
+  }
+
+  if (logicalSkip & LOGICAL_SIDE_I_END) {
     if (writingMode.IsVertical()) {
-      skip |= eSideBitsBottom;
+      skip |= 1 << NS_SIDE_BOTTOM;
     } else {
-      skip |= writingMode.IsBidiLTR() ? eSideBitsRight : eSideBitsLeft;
-    }
-  }
+      skip |= 1 << (writingMode.IsBidiLTR() ? NS_SIDE_RIGHT : NS_SIDE_LEFT);
+    }
+  }
+
   return skip;
 }
 
 nsRect
 nsIFrame::GetPaddingRectRelativeToSelf() const
 {
   nsMargin border(GetUsedBorder());
   border.ApplySkipSides(GetSkipSides());
@@ -1137,17 +1138,17 @@ nsIFrame::GetContentRect() const
 {
   return GetContentRectRelativeToSelf() + GetPosition();
 }
 
 bool
 nsIFrame::ComputeBorderRadii(const nsStyleCorners& aBorderRadius,
                              const nsSize& aFrameSize,
                              const nsSize& aBorderArea,
-                             Sides aSkipSides,
+                             int aSkipSides,
                              nscoord aRadii[8])
 {
   // Percentages are relative to whichever side they're on.
   NS_FOR_CSS_HALF_CORNERS(i) {
     const nsStyleCoord c = aBorderRadius.Get(i);
     nscoord axis =
       NS_HALF_CORNER_IS_X(i) ? aFrameSize.width : aFrameSize.height;
 
@@ -1158,38 +1159,38 @@ nsIFrame::ComputeBorderRadii(const nsSty
         aRadii[i] = 0;
       }
     } else {
       NS_NOTREACHED("ComputeBorderRadii: bad unit");
       aRadii[i] = 0;
     }
   }
 
-  if (aSkipSides.Top()) {
+  if (aSkipSides & (1 << NS_SIDE_TOP)) {
     aRadii[NS_CORNER_TOP_LEFT_X] = 0;
     aRadii[NS_CORNER_TOP_LEFT_Y] = 0;
     aRadii[NS_CORNER_TOP_RIGHT_X] = 0;
     aRadii[NS_CORNER_TOP_RIGHT_Y] = 0;
   }
 
-  if (aSkipSides.Right()) {
+  if (aSkipSides & (1 << NS_SIDE_RIGHT)) {
     aRadii[NS_CORNER_TOP_RIGHT_X] = 0;
     aRadii[NS_CORNER_TOP_RIGHT_Y] = 0;
     aRadii[NS_CORNER_BOTTOM_RIGHT_X] = 0;
     aRadii[NS_CORNER_BOTTOM_RIGHT_Y] = 0;
   }
 
-  if (aSkipSides.Bottom()) {
+  if (aSkipSides & (1 << NS_SIDE_BOTTOM)) {
     aRadii[NS_CORNER_BOTTOM_RIGHT_X] = 0;
     aRadii[NS_CORNER_BOTTOM_RIGHT_Y] = 0;
     aRadii[NS_CORNER_BOTTOM_LEFT_X] = 0;
     aRadii[NS_CORNER_BOTTOM_LEFT_Y] = 0;
   }
 
-  if (aSkipSides.Left()) {
+  if (aSkipSides & (1 << NS_SIDE_LEFT)) {
     aRadii[NS_CORNER_BOTTOM_LEFT_X] = 0;
     aRadii[NS_CORNER_BOTTOM_LEFT_Y] = 0;
     aRadii[NS_CORNER_TOP_LEFT_X] = 0;
     aRadii[NS_CORNER_TOP_LEFT_Y] = 0;
   }
 
   // css3-background specifies this algorithm for reducing
   // corner radii when they are too big.
@@ -1240,17 +1241,17 @@ nsIFrame::OutsetBorderRadii(nscoord aRad
       aRadii[hc1] += offset;
     if (aRadii[hc2] > 0)
       aRadii[hc2] += offset;
   }
 }
 
 /* virtual */ bool
 nsIFrame::GetBorderRadii(const nsSize& aFrameSize, const nsSize& aBorderArea,
-                         Sides aSkipSides, nscoord aRadii[8]) const
+                         int aSkipSides, nscoord aRadii[8]) const
 {
   if (IsThemed()) {
     // When we're themed, the native theme code draws the border and
     // background, and therefore it doesn't make sense to tell other
     // code that's interested in border-radius that we have any radii.
     //
     // In an ideal world, we might have a way for the them to tell us an
     // border radius, but since we don't, we're better off assuming

--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -4333,17 +4333,17 @@ ReduceRadii(nscoord aXBorder, nscoord aY
  *
  * In other words, we require that the border radius be reduced until the
  * inner border radius at the inner edge of the border is 0 wherever we
  * have scrollbars.
  */
 bool
 ScrollFrameHelper::GetBorderRadii(const nsSize& aFrameSize,
                                   const nsSize& aBorderArea,
-                                  Sides aSkipSides,
+                                  int aSkipSides,
                                   nscoord aRadii[8]) const
 {
   if (!mOuter->nsContainerFrame::GetBorderRadii(aFrameSize, aBorderArea,
                                                 aSkipSides, aRadii)) {
     return false;
   }
 
   // Since we can use GetActualScrollbarSizes (rather than

--- a/layout/generic/nsGfxScrollFrame.h
+++ b/layout/generic/nsGfxScrollFrame.h
@@ -34,17 +34,16 @@ namespace layout {
 class ScrollbarActivity;
 }
 }
 
 namespace mozilla {
 
 class ScrollFrameHelper : public nsIReflowCallback {
 public:
-  typedef nsIFrame::Sides Sides;
   typedef mozilla::CSSIntPoint CSSIntPoint;
   typedef mozilla::layout::ScrollbarActivity ScrollbarActivity;
 
   class AsyncScroll;
 
   ScrollFrameHelper(nsContainerFrame* aOuter, bool aIsRoot);
   ~ScrollFrameHelper();
 
@@ -68,17 +67,17 @@ public:
 
   void AppendScrollPartsTo(nsDisplayListBuilder*   aBuilder,
                            const nsRect&           aDirtyRect,
                            const nsDisplayListSet& aLists,
                            bool                    aCreateLayer,
                            bool                    aPositioned);
 
   bool GetBorderRadii(const nsSize& aFrameSize, const nsSize& aBorderArea,
-                      Sides aSkipSides, nscoord aRadii[8]) const;
+                      int aSkipSides, nscoord aRadii[8]) const;
 
   // nsIReflowCallback
   virtual bool ReflowFinished() MOZ_OVERRIDE;
   virtual void ReflowCallbackCanceled() MOZ_OVERRIDE;
 
   /**
    * @note This method might destroy the frame, pres shell and other objects.
    * Called when the 'curpos' attribute on one of the scrollbars changes.
@@ -476,17 +475,17 @@ public:
                            bool aFirstPass);
   void ReflowContents(ScrollReflowState* aState,
                       const nsHTMLReflowMetrics& aDesiredSize);
   void PlaceScrollArea(const ScrollReflowState& aState,
                        const nsPoint& aScrollPosition);
   nscoord GetIntrinsicVScrollbarWidth(nsRenderingContext *aRenderingContext);
 
   virtual bool GetBorderRadii(const nsSize& aFrameSize, const nsSize& aBorderArea,
-                              Sides aSkipSides, nscoord aRadii[8]) const MOZ_OVERRIDE {
+                              int aSkipSides, nscoord aRadii[8]) const MOZ_OVERRIDE {
     return mHelper.GetBorderRadii(aFrameSize, aBorderArea, aSkipSides, aRadii);
   }
 
   virtual nscoord GetMinWidth(nsRenderingContext *aRenderingContext) MOZ_OVERRIDE;
   virtual nscoord GetPrefWidth(nsRenderingContext *aRenderingContext) MOZ_OVERRIDE;
   virtual nsresult GetPadding(nsMargin& aPadding) MOZ_OVERRIDE;
   virtual bool IsCollapsed() MOZ_OVERRIDE;
   
@@ -825,17 +824,17 @@ public:
   virtual nsSize GetPrefSize(nsBoxLayoutState& aBoxLayoutState) MOZ_OVERRIDE;
   virtual nsSize GetMaxSize(nsBoxLayoutState& aBoxLayoutState) MOZ_OVERRIDE;
   virtual nscoord GetBoxAscent(nsBoxLayoutState& aBoxLayoutState) MOZ_OVERRIDE;
 
   NS_IMETHOD DoLayout(nsBoxLayoutState& aBoxLayoutState) MOZ_OVERRIDE;
   virtual nsresult GetPadding(nsMargin& aPadding) MOZ_OVERRIDE;
 
   virtual bool GetBorderRadii(const nsSize& aFrameSize, const nsSize& aBorderArea,
-                              Sides aSkipSides, nscoord aRadii[8]) const MOZ_OVERRIDE {
+                              int aSkipSides, nscoord aRadii[8]) const MOZ_OVERRIDE {
     return mHelper.GetBorderRadii(aFrameSize, aBorderArea, aSkipSides, aRadii);
   }
 
   nsresult Layout(nsBoxLayoutState& aState);
   void LayoutScrollArea(nsBoxLayoutState& aState, const nsPoint& aScrollPosition);
 
   static bool AddRemoveScrollbar(bool& aHasScrollbar, 
                                    nscoord& aXY, 

--- a/layout/generic/nsIFrame.h
+++ b/layout/generic/nsIFrame.h
@@ -403,18 +403,16 @@ public:
   typedef mozilla::FrameProperties FrameProperties;
   typedef mozilla::layers::Layer Layer;
   typedef mozilla::layout::FrameChildList ChildList;
   typedef mozilla::layout::FrameChildListID ChildListID;
   typedef mozilla::layout::FrameChildListIDs ChildListIDs;
   typedef mozilla::layout::FrameChildListIterator ChildListIterator;
   typedef mozilla::layout::FrameChildListArrayIterator ChildListArrayIterator;
   typedef mozilla::gfx::Matrix Matrix;
-  typedef mozilla::Sides Sides;
-  typedef mozilla::LogicalSides LogicalSides;
 
   NS_DECL_QUERYFRAME_TARGET(nsIFrame)
 
   nsPresContext* PresContext() const {
     return StyleContext()->RuleNode()->PresContext();
   }
 
   /**
@@ -914,20 +912,20 @@ public:
    * large.
    * FIXME: In the long run, we can probably get away with only one of
    * these, especially if we change the way we handle outline-radius (by
    * removing it and inflating the border radius)
    *
    * Return whether any radii are nonzero.
    */
   static bool ComputeBorderRadii(const nsStyleCorners& aBorderRadius,
-                                 const nsSize& aFrameSize,
-                                 const nsSize& aBorderArea,
-                                 Sides aSkipSides,
-                                 nscoord aRadii[8]);
+                                   const nsSize& aFrameSize,
+                                   const nsSize& aBorderArea,
+                                   int aSkipSides,
+                                   nscoord aRadii[8]);
 
   /*
    * Given a set of border radii for one box (e.g., border box), convert
    * it to the equivalent set of radii for another box (e.g., in to
    * padding box, out to outline box) by reducing radii or increasing
    * nonzero radii as appropriate.
    *
    * Indices into aRadii are the NS_CORNER_* constants in nsStyleConsts.h
@@ -943,17 +941,17 @@ public:
   /**
    * Fill in border radii for this frame.  Return whether any are nonzero.
    * Indices into aRadii are the NS_CORNER_* constants in nsStyleConsts.h
    * aSkipSides is a union of SIDE_BIT_LEFT/RIGHT/TOP/BOTTOM bits that says
    * which side(s) to skip.
    */
   virtual bool GetBorderRadii(const nsSize& aFrameSize,
                               const nsSize& aBorderArea,
-                              Sides aSkipSides,
+                              int aSkipSides,
                               nscoord aRadii[8]) const;
   bool GetBorderRadii(nscoord aRadii[8]) const;
 
   bool GetPaddingBoxBorderRadii(nscoord aRadii[8]) const;
   bool GetContentBoxBorderRadii(nscoord aRadii[8]) const;
 
   /**
    * Get the position of the frame's baseline, relative to the top of
@@ -2300,33 +2298,31 @@ public:
 
   /**
    * Removes any stored overflow rects (visual and scrollable) from the frame.
    * Returns true if the overflow changed.
    */
   bool ClearOverflowRects();
 
   /**
-   * Determine whether borders, padding, margins etc should NOT be applied
-   * on certain sides of the frame.
-   * @see mozilla::Sides in gfx/2d/BaseMargin.h
-   * @see mozilla::LogicalSides in layout/generic/WritingModes.h
+   * Determine whether borders should not be painted on certain sides of the
+   * frame.
    *
    * @note (See also bug 743402, comment 11) GetSkipSides() checks to see
    *       if this frame has a previous or next continuation to determine
    *       if a side should be skipped.
    *       Unfortunately, this only works after reflow has been completed. In
    *       lieu of this, during reflow, an nsHTMLReflowState parameter can be
    *       passed in, indicating that it should be used to determine if sides
    *       should be skipped during reflow.
    */
-  Sides GetSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const;
-  virtual LogicalSides
+  int GetSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const;
+  virtual int
   GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const {
-    return LogicalSides();
+    return 0;
   }
 
   /**
    * @returns true if this frame is selected.
    */
   bool IsSelected() const;
 
   /**

--- a/layout/generic/nsImageFrame.cpp
+++ b/layout/generic/nsImageFrame.cpp
@@ -1831,29 +1831,29 @@ nsImageFrame::List(FILE* out, const char
       uri->GetAsciiSpec(uristr);
       str += nsPrintfCString(" [src=%s]", uristr.get());
     }
   }
   fprintf_stderr(out, "%s\n", str.get());
 }
 #endif
 
-nsIFrame::LogicalSides
+int
 nsImageFrame::GetLogicalSkipSides(const nsHTMLReflowState* aReflowState) const
 {
   if (MOZ_UNLIKELY(StyleBorder()->mBoxDecorationBreak ==
                      NS_STYLE_BOX_DECORATION_BREAK_CLONE)) {
-    return LogicalSides();
+    return 0;
   }
-  LogicalSides skip;
+  int skip = 0;
   if (nullptr != GetPrevInFlow()) {
-    skip |= eLogicalSideBitsBStart;
+    skip |= LOGICAL_SIDE_B_START;
   }
   if (nullptr != GetNextInFlow()) {
-    skip |= eLogicalSideBitsBEnd;
+    skip |= LOGICAL_SIDE_B_END;
   }
   return skip;
 }
 
 nsresult
 nsImageFrame::GetIntrinsicImageSize(nsSize& aSize)
 {
   if (mIntrinsicSize.width.GetUnit() == eStyleUnit_Coord &&

--- a/layout/generic/nsImageFrame.h
+++ b/layout/generic/nsImageFrame.h
@@ -113,17 +113,17 @@ public:
   }
 
 #ifdef DEBUG_FRAME_DUMP
   virtual nsresult GetFrameName(nsAString& aResult) const MOZ_OVERRIDE;
   void List(FILE* out = stderr, const char* aPrefix = "", 
             uint32_t aFlags = 0) const MOZ_OVERRIDE;
 #endif
 
-  virtual LogicalSides GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
+  virtual int GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
 
   nsresult GetIntrinsicImageSize(nsSize& aSize);
 
   static void ReleaseGlobals() {
     if (gIconLoad) {
       gIconLoad->Shutdown();
       NS_RELEASE(gIconLoad);
     }

--- a/layout/generic/nsInlineFrame.cpp
+++ b/layout/generic/nsInlineFrame.cpp
@@ -875,67 +875,67 @@ nsInlineFrame::PushFrames(nsPresContext*
   if (aState.mLineLayout) {
     aState.mLineLayout->SetDirtyNextLine();
   }
 }
 
 
 //////////////////////////////////////////////////////////////////////
 
-nsIFrame::LogicalSides
+int
 nsInlineFrame::GetLogicalSkipSides(const nsHTMLReflowState* aReflowState) const
 {
   if (MOZ_UNLIKELY(StyleBorder()->mBoxDecorationBreak ==
                      NS_STYLE_BOX_DECORATION_BREAK_CLONE)) {
-    return LogicalSides();
+    return 0;
   }
 
-  LogicalSides skip;
+  int skip = 0;
   if (!IsFirst()) {
     nsInlineFrame* prev = (nsInlineFrame*) GetPrevContinuation();
     if ((GetStateBits() & NS_INLINE_FRAME_BIDI_VISUAL_STATE_IS_SET) ||
         (prev && (prev->mRect.height || prev->mRect.width))) {
       // Prev continuation is not empty therefore we don't render our start
       // border edge.
-      skip |= eLogicalSideBitsIStart;
+      skip |= LOGICAL_SIDE_I_START;
     }
     else {
       // If the prev continuation is empty, then go ahead and let our start
       // edge border render.
     }
   }
   if (!IsLast()) {
     nsInlineFrame* next = (nsInlineFrame*) GetNextContinuation();
     if ((GetStateBits() & NS_INLINE_FRAME_BIDI_VISUAL_STATE_IS_SET) ||
         (next && (next->mRect.height || next->mRect.width))) {
       // Next continuation is not empty therefore we don't render our end
       // border edge.
-      skip |= eLogicalSideBitsIEnd;
+      skip |= LOGICAL_SIDE_I_END;
     }
     else {
       // If the next continuation is empty, then go ahead and let our end
       // edge border render.
     }
   }
 
   if (GetStateBits() & NS_FRAME_PART_OF_IBSPLIT) {
     // All but the last part of an {ib} split should skip the "end" side (as
     // determined by this frame's direction) and all but the first part of such
     // a split should skip the "start" side.  But figuring out which part of
     // the split we are involves getting our first continuation, which might be
     // expensive.  So don't bother if we already have the relevant bits set.
-    if (skip != LogicalSides(eLogicalSideBitsIBoth)) {
+    if (skip != LOGICAL_SIDES_I_BOTH) {
       // We're missing one of the skip bits, so check whether we need to set it.
       // Only get the first continuation once, as an optimization.
       nsIFrame* firstContinuation = FirstContinuation();
       if (firstContinuation->FrameIsNonLastInIBSplit()) {
-        skip |= eLogicalSideBitsIEnd;
+        skip |= LOGICAL_SIDE_I_END;
       }
       if (firstContinuation->FrameIsNonFirstInIBSplit()) {
-        skip |= eLogicalSideBitsIStart;
+        skip |= LOGICAL_SIDE_I_START;
       }
     }
   }
 
   return skip;
 }
 
 nscoord

--- a/layout/generic/nsInlineFrame.h
+++ b/layout/generic/nsInlineFrame.h
@@ -122,17 +122,17 @@ protected:
       mLineContainer = nullptr;
       mLineLayout = nullptr;
       mSetParentPointer = false;
     }
   };
 
   nsInlineFrame(nsStyleContext* aContext) : nsContainerFrame(aContext) {}
 
-  virtual LogicalSides GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
+  virtual int GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
 
   void ReflowFrames(nsPresContext* aPresContext,
                     const nsHTMLReflowState& aReflowState,
                     InlineReflowState& rs,
                     nsHTMLReflowMetrics& aMetrics,
                     nsReflowStatus& aStatus);
 
   void ReflowInlineFrame(nsPresContext* aPresContext,

--- a/layout/generic/nsSplittableFrame.cpp
+++ b/layout/generic/nsSplittableFrame.cpp
@@ -7,18 +7,16 @@
  * base class for rendering objects that can be split across lines,
  * columns, or pages
  */
 
 #include "nsSplittableFrame.h"
 #include "nsContainerFrame.h"
 #include "nsIFrameInlines.h"
 
-using namespace mozilla;
-
 NS_IMPL_FRAMEARENA_HELPERS(nsSplittableFrame)
 
 void
 nsSplittableFrame::Init(nsIContent*       aContent,
                         nsContainerFrame* aParent,
                         nsIFrame*         aPrevInFlow)
 {
   nsFrame::Init(aContent, aParent, aPrevInFlow);
@@ -232,52 +230,52 @@ nsSplittableFrame::GetEffectiveComputedB
   }
 
   bSize -= aConsumedBSize;
 
   // We may have stretched the frame beyond its computed height. Oh well.
   return std::max(0, bSize);
 }
 
-nsIFrame::LogicalSides
+int
 nsSplittableFrame::GetLogicalSkipSides(const nsHTMLReflowState* aReflowState) const
 {
   if (IS_TRUE_OVERFLOW_CONTAINER(this)) {
-    return LogicalSides(eLogicalSideBitsBBoth);
+    return LOGICAL_SIDES_B_BOTH;
   }
 
   if (MOZ_UNLIKELY(StyleBorder()->mBoxDecorationBreak ==
                      NS_STYLE_BOX_DECORATION_BREAK_CLONE)) {
-    return LogicalSides();
+    return 0;
   }
 
-  LogicalSides skip;
+  int skip = 0;
   if (GetPrevInFlow()) {
-    skip |= eLogicalSideBitsBStart;
+    skip |= LOGICAL_SIDE_B_START;
   }
 
   if (aReflowState) {
     // We're in the midst of reflow right now, so it's possible that we haven't
     // created a nif yet. If our content height is going to exceed our available
     // height, though, then we're going to need a next-in-flow, it just hasn't
     // been created yet.
 
     if (NS_UNCONSTRAINEDSIZE != aReflowState->AvailableBSize()) {
       nscoord effectiveCH = this->GetEffectiveComputedBSize(*aReflowState);
       if (effectiveCH != NS_INTRINSICSIZE &&
           effectiveCH > aReflowState->AvailableBSize()) {
         // Our content height is going to exceed our available height, so we're
         // going to need a next-in-flow.
-        skip |= eLogicalSideBitsBEnd;
+        skip |= LOGICAL_SIDE_B_END;
       }
     }
   } else {
     nsIFrame* nif = GetNextInFlow();
     if (nif && !IS_TRUE_OVERFLOW_CONTAINER(nif)) {
-      skip |= eLogicalSideBitsBEnd;
+      skip |= LOGICAL_SIDE_B_END;
     }
   }
 
  return skip;
 }
 
 #ifdef DEBUG
 void

--- a/layout/generic/nsSplittableFrame.h
+++ b/layout/generic/nsSplittableFrame.h
@@ -90,17 +90,17 @@ protected:
    * computed block size, minus the block size consumed by any previous in-flows.
    */
   nscoord GetEffectiveComputedBSize(const nsHTMLReflowState& aReflowState,
                                     nscoord aConsumed = NS_INTRINSICSIZE) const;
 
   /**
    * @see nsIFrame::GetLogicalSkipSides()
    */
-  virtual LogicalSides GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
+  virtual int GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
 
 #ifdef DEBUG
   virtual void DumpBaseRegressionData(nsPresContext* aPresContext, FILE* out, int32_t aIndent) MOZ_OVERRIDE;
 #endif
 
   nsIFrame*   mPrevContinuation;
   nsIFrame*   mNextContinuation;
 };

--- a/layout/mathml/nsMathMLChar.cpp
+++ b/layout/mathml/nsMathMLChar.cpp
@@ -1959,17 +1959,17 @@ public:
 private:
   nsRect mRect;
 };
 
 void nsDisplayMathMLCharDebug::Paint(nsDisplayListBuilder* aBuilder,
                                      nsRenderingContext* aCtx)
 {
   // for visual debug
-  Sides skipSides;
+  int skipSides = 0;
   nsPresContext* presContext = mFrame->PresContext();
   nsStyleContext* styleContext = mFrame->StyleContext();
   nsRect rect = mRect + ToReferenceFrame();
   nsCSSRendering::PaintBorder(presContext, *aCtx, mFrame,
                               mVisibleRect, rect, styleContext, skipSides);
   nsCSSRendering::PaintOutline(presContext, *aCtx, mFrame,
                                mVisibleRect, rect, styleContext);
 }

--- a/layout/style/nsComputedDOMStylePropertyList.h
+++ b/layout/style/nsComputedDOMStylePropertyList.h
@@ -90,17 +90,16 @@ COMPUTED_STYLE_PROP(border_spacing,     
 //// COMPUTED_STYLE_PROP(border_top,               BorderTop)
 COMPUTED_STYLE_PROP(border_top_color,              BorderTopColor)
 COMPUTED_STYLE_PROP(border_top_left_radius,        BorderTopLeftRadius)
 COMPUTED_STYLE_PROP(border_top_right_radius,       BorderTopRightRadius)
 COMPUTED_STYLE_PROP(border_top_style,              BorderTopStyle)
 COMPUTED_STYLE_PROP(border_top_width,              BorderTopWidth)
 //// COMPUTED_STYLE_PROP(border_width,             BorderWidth)
 COMPUTED_STYLE_PROP(bottom,                        Bottom)
-COMPUTED_STYLE_PROP(box_decoration_break,          BoxDecorationBreak)
 COMPUTED_STYLE_PROP(box_shadow,                    BoxShadow)
 COMPUTED_STYLE_PROP(box_sizing,                    BoxSizing)
 COMPUTED_STYLE_PROP(caption_side,                  CaptionSide)
 COMPUTED_STYLE_PROP(clear,                         Clear)
 COMPUTED_STYLE_PROP(clip,                          Clip)
 COMPUTED_STYLE_PROP(color,                         Color)
 COMPUTED_STYLE_PROP(content,                       Content)
 COMPUTED_STYLE_PROP(counter_increment,             CounterIncrement)

--- a/layout/style/nsStyleConsts.h
+++ b/layout/style/nsStyleConsts.h
@@ -9,21 +9,20 @@
 #define nsStyleConsts_h___
 
 #include "gfxRect.h"
 #include "nsFont.h"
 
 // XXX fold this into nsStyleContext and group by nsStyleXXX struct
 
 // Indices into border/padding/margin arrays
-namespace mozilla {
-namespace css {
-typedef mozilla::Side Side;
-}
-}
+#define NS_SIDE_TOP     mozilla::css::eSideTop
+#define NS_SIDE_RIGHT   mozilla::css::eSideRight
+#define NS_SIDE_BOTTOM  mozilla::css::eSideBottom
+#define NS_SIDE_LEFT    mozilla::css::eSideLeft
 
 #define NS_FOR_CSS_SIDES(var_) for (mozilla::css::Side var_ = NS_SIDE_TOP; var_ <= NS_SIDE_LEFT; var_++)
 static inline mozilla::css::Side operator++(mozilla::css::Side& side, int) {
     NS_PRECONDITION(side >= NS_SIDE_TOP &&
                     side <= NS_SIDE_LEFT, "Out of range side");
     side = mozilla::css::Side(side + 1);
     return side;
 }

--- a/layout/tables/celldata.h
+++ b/layout/tables/celldata.h
@@ -196,21 +196,21 @@ public:
 
   nscoord GetTopEdge(BCBorderOwner& aOwner,
                      bool&        aStart) const;
 
   void SetTopEdge(BCBorderOwner aOwner,
                   nscoord       aSize,
                   bool          aStart);
 
-  BCPixelSize GetCorner(mozilla::Side&       aCornerOwner,
+  BCPixelSize GetCorner(mozilla::css::Side&       aCornerOwner,
                         bool&  aBevel) const;
 
   void SetCorner(BCPixelSize aSubSize,
-                 mozilla::Side aOwner,
+                 mozilla::css::Side aOwner,
                  bool    aBevel);
 
   bool IsLeftStart() const;
 
   void SetLeftStart(bool aValue);
 
   bool IsTopStart() const;
 
@@ -224,17 +224,17 @@ protected:
                               //   dominant plane (for example, if corner is
                               //   owned by the segment to its top or bottom,
                               //   then the size is the max of the border
                               //   sizes of the segments to its left or right.
   unsigned mLeftOwner:     4; // owner of left border
   unsigned mTopOwner:      4; // owner of top border
   unsigned mLeftStart:     1; // set if this is the start of a vertical border segment
   unsigned mTopStart:      1; // set if this is the start of a horizontal border segment
-  unsigned mCornerSide:    2; // mozilla::Side of the owner of the upper left corner relative to the corner
+  unsigned mCornerSide:    2; // mozilla::css::Side of the owner of the upper left corner relative to the corner
   unsigned mCornerBevel:   1; // is the corner beveled (only two segments, perpendicular, not dashed or dotted).
 };
 
 // BCCellData entries replace CellData entries in the cell map if the border collapsing model is in
 // effect. BCData for a row and col entry contains the left and top borders of cell at that row and
 // col and the corner connecting the two. The right borders of the cells in the last col and the bottom
 // borders of the last row are stored in separate BCData entries in the cell map.
 class BCCellData : public CellData
@@ -444,26 +444,26 @@ inline void BCData::SetTopEdge(BCBorderO
                                nscoord        aSize,
                                bool           aStart)
 {
   mTopOwner = aOwner;
   mTopSize  = (aSize > MAX_BORDER_WIDTH) ? MAX_BORDER_WIDTH : aSize;
   mTopStart = aStart;
 }
 
-inline BCPixelSize BCData::GetCorner(mozilla::Side& aOwnerSide,
+inline BCPixelSize BCData::GetCorner(mozilla::css::Side& aOwnerSide,
                                      bool&       aBevel) const
 {
-  aOwnerSide = mozilla::Side(mCornerSide);
+  aOwnerSide = mozilla::css::Side(mCornerSide);
   aBevel     = (bool)mCornerBevel;
   return mCornerSubSize;
 }
 
 inline void BCData::SetCorner(BCPixelSize aSubSize,
-                              mozilla::Side aOwnerSide,
+                              mozilla::css::Side aOwnerSide,
                               bool    aBevel)
 {
   mCornerSubSize = aSubSize;
   mCornerSide    = aOwnerSide;
   mCornerBevel   = aBevel;
 }
 
 inline bool BCData::IsLeftStart() const

--- a/layout/tables/nsCellMap.cpp
+++ b/layout/tables/nsCellMap.cpp
@@ -723,17 +723,17 @@ nsTableCellMap::Dump(char* aString) cons
   while (cellMap) {
     cellMap->Dump(nullptr != mBCInfo);
     cellMap = cellMap->GetNextSibling();
   }
   if (nullptr != mBCInfo) {
     printf("***** bottom borders *****\n");
     nscoord       size;
     BCBorderOwner owner;
-    mozilla::Side side;
+    mozilla::css::Side side;
     bool          segStart;
     bool          bevel;
     int32_t       colIndex;
     int32_t numCols = mBCInfo->mBottomBorders.Length();
     for (int32_t i = 0; i <= 2; i++) {
 
       printf("\n          ");
       for (colIndex = 0; colIndex < numCols; colIndex++) {
@@ -965,17 +965,17 @@ nsTableCellMap::ResetTopStart(uint8_t   
   }
 }
 
 // store the aSide border segment at coord = (aRowIndex, aColIndex). For top/left, store
 // the info at coord. For bottom/left store it at the adjacent location so that it is
 // top/left at that location. If the new location is at the right or bottom edge of the
 // table, then store it one of the special arrays (right most borders, bottom most borders).
 void
-nsTableCellMap::SetBCBorderEdge(mozilla::Side aSide,
+nsTableCellMap::SetBCBorderEdge(mozilla::css::Side aSide,
                                 nsCellMap&    aCellMap,
                                 uint32_t      aCellMapStart,
                                 uint32_t      aRowIndex,
                                 uint32_t      aColIndex,
                                 uint32_t      aLength,
                                 BCBorderOwner aOwner,
                                 nscoord       aSize,
                                 bool          aChanged)
@@ -1065,17 +1065,17 @@ nsTableCellMap::SetBCBorderEdge(mozilla:
 // (aRowIndex, aColIndex). For eTopRight, store it in the entry to the right where
 // it would be top left. For eBottomRight, store it in the entry to the bottom. etc.
 void
 nsTableCellMap::SetBCBorderCorner(Corner      aCorner,
                                   nsCellMap&  aCellMap,
                                   uint32_t    aCellMapStart,
                                   uint32_t    aRowIndex,
                                   uint32_t    aColIndex,
-                                  mozilla::Side aOwner,
+                                  mozilla::css::Side aOwner,
                                   nscoord     aSubSize,
                                   bool        aBevel,
                                   bool        aIsBottomRight)
 {
   if (!mBCInfo) ABORT0();
 
   if (aIsBottomRight) {
     mBCInfo->mLowerRightCorner.SetCorner(aSubSize, aOwner, aBevel);
@@ -2579,17 +2579,17 @@ void nsCellMap::Dump(bool aIsBorderColla
         }
       } else {
         printf("----  ");
       }
     }
     if (aIsBorderCollapse) {
       nscoord       size;
       BCBorderOwner owner;
-      mozilla::Side side;
+      mozilla::css::Side side;
       bool          segStart;
       bool          bevel;
       for (int32_t i = 0; i <= 2; i++) {
         printf("\n          ");
         for (colIndex = 0; colIndex < colCount; colIndex++) {
           BCCellData* cd = (BCCellData *)row[colIndex];
           if (cd) {
             if (0 == i) {

--- a/layout/tables/nsCellMap.h
+++ b/layout/tables/nsCellMap.h
@@ -199,32 +199,32 @@ public:
   void ExpandZeroColSpans();
 
   void ResetTopStart(uint8_t    aSide,
                      nsCellMap& aCellMap,
                      uint32_t   aYPos,
                      uint32_t   aXPos,
                      bool       aIsLowerRight = false);
 
-  void SetBCBorderEdge(mozilla::Side aEdge,
+  void SetBCBorderEdge(mozilla::css::Side aEdge,
                        nsCellMap&    aCellMap,
                        uint32_t      aCellMapStart,
                        uint32_t      aYPos,
                        uint32_t      aXPos,
                        uint32_t      aLength,
                        BCBorderOwner aOwner,
                        nscoord       aSize,
                        bool          aChanged);
 
   void SetBCBorderCorner(::Corner    aCorner,
                          nsCellMap&  aCellMap,
                          uint32_t    aCellMapStart,
                          uint32_t    aYPos,
                          uint32_t    aXPos,
-                         mozilla::Side aOwner,
+                         mozilla::css::Side aOwner,
                          nscoord     aSubSize,
                          bool        aBevel,
                          bool        aIsBottomRight = false);
 
   /** dump a representation of the cell map to stdout for debugging */
 #ifdef DEBUG
   void Dump(char* aString = nullptr) const;
 #endif

--- a/layout/tables/nsTableCellFrame.cpp
+++ b/layout/tables/nsTableCellFrame.cpp
@@ -540,30 +540,30 @@ nsTableCellFrame::BuildDisplayList(nsDis
   // This isn't a problem since it won't have a real background except for
   // event handling. We do not call BuildDisplayListForNonBlockChildren
   // because that/ would put the child's background in the Content() list
   // which isn't right (e.g., would end up on top of our child floats for
   // event handling).
   BuildDisplayListForChild(aBuilder, kid, aDirtyRect, aLists);
 }
 
-nsIFrame::LogicalSides
+int
 nsTableCellFrame::GetLogicalSkipSides(const nsHTMLReflowState* aReflowState) const
 {
   if (MOZ_UNLIKELY(StyleBorder()->mBoxDecorationBreak ==
                      NS_STYLE_BOX_DECORATION_BREAK_CLONE)) {
-    return LogicalSides();
+    return 0;
   }
 
-  LogicalSides skip;
+  int skip = 0;
   if (nullptr != GetPrevInFlow()) {
-    skip |= eLogicalSideBitsBStart;
+    skip |= LOGICAL_SIDE_B_START;
   }
   if (nullptr != GetNextInFlow()) {
-    skip |= eLogicalSideBitsBEnd;
+    skip |= LOGICAL_SIDE_B_END;
   }
   return skip;
 }
 
 /* virtual */ nsMargin
 nsTableCellFrame::GetBorderOverflow()
 {
   return nsMargin(0, 0, 0, 0);
@@ -1104,17 +1104,17 @@ nsBCTableCellFrame::GetUsedBorder() cons
   nsMargin result;
   GetBorderWidth(result);
   return result;
 }
 
 /* virtual */ bool
 nsBCTableCellFrame::GetBorderRadii(const nsSize& aFrameSize,
                                    const nsSize& aBorderArea,
-                                   Sides aSkipSides,
+                                   int aSkipSides,
                                    nscoord aRadii[8]) const
 {
   NS_FOR_CSS_HALF_CORNERS(corner) {
     aRadii[corner] = 0;
   }
   return false;
 }
 

--- a/layout/tables/nsTableCellFrame.h
+++ b/layout/tables/nsTableCellFrame.h
@@ -217,17 +217,17 @@ public:
     return nsContainerFrame::IsFrameOfType(aFlags & ~(nsIFrame::eTablePart));
   }
   
   virtual void InvalidateFrame(uint32_t aDisplayItemKey = 0) MOZ_OVERRIDE;
   virtual void InvalidateFrameWithRect(const nsRect& aRect, uint32_t aDisplayItemKey = 0) MOZ_OVERRIDE;
   virtual void InvalidateFrameForRemoval() MOZ_OVERRIDE { InvalidateFrameSubtree(); }
 
 protected:
-  virtual LogicalSides GetLogicalSkipSides(const nsHTMLReflowState* aReflowState= nullptr) const MOZ_OVERRIDE;
+  virtual int GetLogicalSkipSides(const nsHTMLReflowState* aReflowState= nullptr) const MOZ_OVERRIDE;
 
   /**
    * GetBorderOverflow says how far the cell's own borders extend
    * outside its own bounds.  In the separated borders model this should
    * just be zero (as it is for most frames), but in the collapsed
    * borders model (for which nsBCTableCellFrame overrides this virtual
    * method), it considers the extents of the collapsed border.
    */
@@ -296,17 +296,17 @@ public:
 
   ~nsBCTableCellFrame();
 
   virtual nsIAtom* GetType() const MOZ_OVERRIDE;
 
   virtual nsMargin GetUsedBorder() const MOZ_OVERRIDE;
   virtual bool GetBorderRadii(const nsSize& aFrameSize,
                               const nsSize& aBorderArea,
-                              Sides aSkipSides,
+                              int aSkipSides,
                               nscoord aRadii[8]) const MOZ_OVERRIDE;
 
   // Get the *inner half of the border only*, in twips.
   virtual nsMargin* GetBorderWidth(nsMargin& aBorder) const MOZ_OVERRIDE;
 
   // Get the *inner half of the border only*, in pixels.
   BCPixelSize GetBorderWidth(mozilla::css::Side aSide) const;
 

--- a/layout/tables/nsTableColGroupFrame.cpp
+++ b/layout/tables/nsTableColGroupFrame.cpp
@@ -9,18 +9,16 @@
 #include "nsStyleConsts.h"
 #include "nsPresContext.h"
 #include "nsHTMLParts.h"
 #include "nsGkAtoms.h"
 #include "nsCOMPtr.h"
 #include "nsCSSRendering.h"
 #include "nsIPresShell.h"
 
-using namespace mozilla;
-
 #define COL_GROUP_TYPE_BITS          (NS_FRAME_STATE_BIT(30) | \
                                       NS_FRAME_STATE_BIT(31))
 #define COL_GROUP_TYPE_OFFSET        30
 
 nsTableColGroupType 
 nsTableColGroupFrame::GetColType() const 
 {
   return (nsTableColGroupType)((mState & COL_GROUP_TYPE_BITS) >> COL_GROUP_TYPE_OFFSET);
@@ -325,30 +323,30 @@ nsTableColGroupFrame::RemoveFrame(ChildL
                                            eColAnonymousColGroup, true);
     }
   }
   else {
     mFrames.DestroyFrame(aOldFrame);
   }
 }
 
-nsIFrame::LogicalSides
+int
 nsTableColGroupFrame::GetLogicalSkipSides(const nsHTMLReflowState* aReflowState) const
 {
   if (MOZ_UNLIKELY(StyleBorder()->mBoxDecorationBreak ==
                      NS_STYLE_BOX_DECORATION_BREAK_CLONE)) {
-    return LogicalSides();
+    return 0;
   }
 
-  LogicalSides skip;
+  int skip = 0;
   if (nullptr != GetPrevInFlow()) {
-    skip |= eLogicalSideBitsBStart;
+    skip |= LOGICAL_SIDE_B_START;
   }
   if (nullptr != GetNextInFlow()) {
-    skip |= eLogicalSideBitsBEnd;
+    skip |= LOGICAL_SIDE_B_END;
   }
   return skip;
 }
 
 void
 nsTableColGroupFrame::Reflow(nsPresContext*          aPresContext,
                                        nsHTMLReflowMetrics&     aDesiredSize,
                                        const nsHTMLReflowState& aReflowState,

--- a/layout/tables/nsTableColGroupFrame.h
+++ b/layout/tables/nsTableColGroupFrame.h
@@ -202,17 +202,17 @@ public:
   virtual void InvalidateFrameForRemoval() MOZ_OVERRIDE { InvalidateFrameSubtree(); }
 
 protected:
   nsTableColGroupFrame(nsStyleContext* aContext);
 
   void InsertColsReflow(int32_t                   aColIndex,
                         const nsFrameList::Slice& aCols);
 
-  virtual LogicalSides GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
+  virtual int GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
 
   // data members
   int32_t mColCount;
   // the starting column index this col group represents. Must be >= 0. 
   int32_t mStartColIndex;
 
   // border width in pixels
   BCPixelSize mTopContBorderWidth;

--- a/layout/tables/nsTableFrame.cpp
+++ b/layout/tables/nsTableFrame.cpp
@@ -1378,46 +1378,46 @@ nsTableFrame::PaintTableBorderBackground
   nsMargin deflate = GetDeflationForBackground(presContext);
   // If 'deflate' is (0,0,0,0) then we'll paint the table background
   // in a separate display item, so don't do it here.
   nsresult rv = painter.PaintTable(this, deflate, deflate != nsMargin(0, 0, 0, 0));
   if (NS_FAILED(rv)) return;
 
   if (StyleVisibility()->IsVisible()) {
     if (!IsBorderCollapse()) {
-      Sides skipSides = GetSkipSides();
+      int skipSides = GetSkipSides();
       nsRect rect(aPt, mRect.Size());
       nsCSSRendering::PaintBorder(presContext, aRenderingContext, this,
                                   aDirtyRect, rect, mStyleContext, skipSides);
     }
     else {
       // XXX we should probably get rid of this translation at some stage
       // But that would mean modifying PaintBCBorders, ugh
       nsRenderingContext::AutoPushTranslation translate(&aRenderingContext, aPt);
       PaintBCBorders(aRenderingContext, aDirtyRect - aPt);
     }
   }
 }
 
-nsIFrame::LogicalSides
+int
 nsTableFrame::GetLogicalSkipSides(const nsHTMLReflowState* aReflowState) const
 {
   if (MOZ_UNLIKELY(StyleBorder()->mBoxDecorationBreak ==
                      NS_STYLE_BOX_DECORATION_BREAK_CLONE)) {
-    return LogicalSides();
-  }
-
-  LogicalSides skip;
+    return 0;
+  }
+
+  int skip = 0;
   // frame attribute was accounted for in nsHTMLTableElement::MapTableBorderInto
   // account for pagination
   if (nullptr != GetPrevInFlow()) {
-    skip |= eLogicalSideBitsBStart;
+    skip |= LOGICAL_SIDE_B_START;
   }
   if (nullptr != GetNextInFlow()) {
-    skip |= eLogicalSideBitsBEnd;
+    skip |= LOGICAL_SIDE_B_END;
   }
   return skip;
 }
 
 void
 nsTableFrame::SetColumnDimensions(nscoord         aHeight,
                                   const nsMargin& aBorderPadding)
 {

--- a/layout/tables/nsTableFrame.h
+++ b/layout/tables/nsTableFrame.h
@@ -575,17 +575,17 @@ protected:
     */
   nsTableFrame(nsStyleContext* aContext);
 
   /** destructor, responsible for mColumnLayoutData */
   virtual ~nsTableFrame();
 
   void InitChildReflowState(nsHTMLReflowState& aReflowState);
 
-  virtual LogicalSides GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
+  virtual int GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
 
 public:
   bool IsRowInserted() const;
   void   SetRowInserted(bool aValue);
 
 protected:
     
   // A helper function to reflow a header or footer with unconstrained height

--- a/layout/tables/nsTableRowFrame.cpp
+++ b/layout/tables/nsTableRowFrame.cpp
@@ -584,30 +584,30 @@ nsTableRowFrame::BuildDisplayList(nsDisp
       // cases.
       item = new (aBuilder) nsDisplayTableRowBackground(aBuilder, this);
       aLists.BorderBackground()->AppendNewToTop(item);
     }
   }
   nsTableFrame::DisplayGenericTablePart(aBuilder, this, aDirtyRect, aLists, item);
 }
 
-nsIFrame::LogicalSides
+int
 nsTableRowFrame::GetLogicalSkipSides(const nsHTMLReflowState* aReflowState) const
 {
   if (MOZ_UNLIKELY(StyleBorder()->mBoxDecorationBreak ==
                      NS_STYLE_BOX_DECORATION_BREAK_CLONE)) {
-    return LogicalSides();
+    return 0;
   }
 
-  LogicalSides skip;
+  int skip = 0;
   if (nullptr != GetPrevInFlow()) {
-    skip |= eLogicalSideBitsBStart;
+    skip |= LOGICAL_SIDE_B_START;
   }
   if (nullptr != GetNextInFlow()) {
-    skip |= eLogicalSideBitsBEnd;
+    skip |= LOGICAL_SIDE_B_END;
   }
   return skip;
 }
 
 // Calculate the cell's actual height given its pass2  height.
 // Takes into account the specified height (in the style).
 // Modifies the desired height that is passed in.
 nsresult

--- a/layout/tables/nsTableRowFrame.h
+++ b/layout/tables/nsTableRowFrame.h
@@ -239,17 +239,17 @@ protected:
     */
   nsTableRowFrame(nsStyleContext *aContext);
 
   void InitChildReflowState(nsPresContext&         aPresContext,
                             const nsSize&           aAvailSize,
                             bool                    aBorderCollapse,
                             nsTableCellReflowState& aReflowState);
   
-  virtual LogicalSides GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
+  virtual int GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
 
   // row-specific methods
 
   nscoord ComputeCellXOffset(const nsHTMLReflowState& aState,
                              nsIFrame*                aKidFrame,
                              const nsMargin&          aKidMargin) const;
   /**
    * Called for incremental/dirty and resize reflows. If aDirtyOnly is true then

--- a/layout/tables/nsTableRowGroupFrame.cpp
+++ b/layout/tables/nsTableRowGroupFrame.cpp
@@ -248,30 +248,30 @@ nsTableRowGroupFrame::BuildDisplayList(n
       item = new (aBuilder) nsDisplayTableRowGroupBackground(aBuilder, this);
       aLists.BorderBackground()->AppendNewToTop(item);
     }
   }  
   nsTableFrame::DisplayGenericTablePart(aBuilder, this, aDirtyRect,
                                         aLists, item, DisplayRows);
 }
 
-nsIFrame::LogicalSides
+int
 nsTableRowGroupFrame::GetLogicalSkipSides(const nsHTMLReflowState* aReflowState) const
 {
   if (MOZ_UNLIKELY(StyleBorder()->mBoxDecorationBreak ==
                      NS_STYLE_BOX_DECORATION_BREAK_CLONE)) {
-    return LogicalSides();
+    return 0;
   }
 
-  LogicalSides skip;
+  int skip = 0;
   if (nullptr != GetPrevInFlow()) {
-    skip |= eLogicalSideBitsBStart;
+    skip |= LOGICAL_SIDE_B_START;
   }
   if (nullptr != GetNextInFlow()) {
-    skip |= eLogicalSideBitsBEnd;
+    skip |= LOGICAL_SIDE_B_END;
   }
   return skip;
 }
 
 // Position and size aKidFrame and update our reflow state. The origin of
 // aKidRect is relative to the upper-left origin of our frame
 void 
 nsTableRowGroupFrame::PlaceChild(nsPresContext*         aPresContext,

--- a/layout/tables/nsTableRowGroupFrame.h
+++ b/layout/tables/nsTableRowGroupFrame.h
@@ -329,17 +329,17 @@ public:
 
 protected:
   nsTableRowGroupFrame(nsStyleContext* aContext);
 
   void InitChildReflowState(nsPresContext&     aPresContext, 
                             bool               aBorderCollapse,
                             nsHTMLReflowState& aReflowState);
   
-  virtual LogicalSides GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
+  virtual int GetLogicalSkipSides(const nsHTMLReflowState* aReflowState = nullptr) const MOZ_OVERRIDE;
 
   void PlaceChild(nsPresContext*         aPresContext,
                   nsRowGroupReflowState& aReflowState,
                   nsIFrame*              aKidFrame,
                   nsHTMLReflowMetrics&   aDesiredSize,
                   const nsRect&          aOriginalKidRect,
                   const nsRect&          aOriginalKidVisualOverflow);
 

--- a/layout/xul/nsGroupBoxFrame.cpp
+++ b/layout/xul/nsGroupBoxFrame.cpp
@@ -118,17 +118,17 @@ nsGroupBoxFrame::BuildDisplayList(nsDisp
   }
 
   BuildDisplayListForChildren(aBuilder, aDirtyRect, aLists);
 }
 
 void
 nsGroupBoxFrame::PaintBorderBackground(nsRenderingContext& aRenderingContext,
     nsPoint aPt, const nsRect& aDirtyRect) {
-  Sides skipSides;
+  int skipSides = 0;
   const nsStyleBorder* borderStyleData = StyleBorder();
   const nsMargin& border = borderStyleData->GetComputedBorder();
   nscoord yoff = 0;
   nsPresContext* presContext = PresContext();
 
   nsRect groupRect;
   nsIFrame* groupBox = GetCaptionBox(presContext, groupRect);