Should not use clipOutRoundedRect when a given rounded rect is empty.

Source/core/rendering/RenderBoxModelObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 1867 matching lines @@
     }
 
     bool clipToOuterBorder = outerBorder.isRounded();
     GraphicsContextStateSaver stateSaver(*graphicsContext, clipToOuterBorder);
     if (clipToOuterBorder) {
         // Clip to the inner and outer radii rects.
         if (bleedAvoidance != BackgroundBleedUseTransparencyLayer)
             graphicsContext->clipRoundedRect(outerBorder);
         // isRenderable() check avoids issue described in https://bugs.webkit.org/show_bug.cgi?id=38787
         // The inside will be clipped out later (in clipBorderSideForComplexInnerPath)
-        if (innerBorder.isRenderable())
+        if (innerBorder.isRenderable() && !innerBorder.isEmpty())
             graphicsContext->clipOutRoundedRect(innerBorder);
     }
 
     // If only one edge visible antialiasing doesn't create seams
     bool antialias = shouldAntialiasLines(graphicsContext) || numEdgesVisible == 1;
     RoundedRect unadjustedInnerBorder = (bleedAvoidance == BackgroundBleedBackgroundOverBorder) ? style->getRoundedInnerBorderFor(rect, includeLogicalLeftEdge, includeLogicalRightEdge) : innerBorder;
     IntPoint innerBorderAdjustment(innerBorder.rect().x() - unadjustedInnerBorder.rect().x(), innerBorder.rect().y() - unadjustedInnerBorder.rect().y());
     if (haveAlphaColor)
         paintTranslucentBorderSides(graphicsContext, style, outerBorder, unadjustedInnerBorder, innerBorderAdjustment, edges, edgesToDraw, bleedAvoidance, includeLogicalLeftEdge, includeLogicalRightEdge, antialias);
     else
@@ skipping 443 matching lines @@
         break;
     }
 
     return RoundedRect(newRect, newRadii);
 }
 
 void RenderBoxModelObject::clipBorderSideForComplexInnerPath(GraphicsContext* graphicsContext, const RoundedRect& outerBorder, const RoundedRect& innerBorder,
     BoxSide side, const class BorderEdge edges[])
 {
     graphicsContext->clip(calculateSideRectIncludingInner(outerBorder, edges, side));
-    graphicsContext->clipOutRoundedRect(calculateAdjustedInnerBorder(innerBorder, side));
+    RoundedRect adjustedInnerRect = calculateAdjustedInnerBorder(innerBorder, side);
+    if (!adjustedInnerRect.isEmpty())
+        graphicsContext->clipOutRoundedRect(adjustedInnerRect);
 }
 
 void RenderBoxModelObject::getBorderEdgeInfo(BorderEdge edges[], const RenderStyle* style, bool includeLogicalLeftEdge, bool includeLogicalRightEdge) const
 {
     bool horizontal = style->isHorizontalWritingMode();
 
     edges[BSTop] = BorderEdge(style->borderTopWidth(),
         resolveColor(style, CSSPropertyBorderTopColor),
         style->borderTopStyle(),
         style->borderTopIsTransparent(),
@@ skipping 465 matching lines @@
     ASSERT(!beforeChild || toBoxModelObject == beforeChild->parent());
     for (RenderObject* child = startChild; child && child != endChild; ) {
         // Save our next sibling as moveChildTo will clear it.
         RenderObject* nextSibling = child->nextSibling();
         moveChildTo(toBoxModelObject, child, beforeChild, fullRemoveInsert);
         child = nextSibling;
     }
 }
 
 } // namespace WebCore