Always anti-alias full border rect paints.

Source/core/paint/BoxBorderPainter.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/BoxBorderPainter.h"
 
 #include "core/paint/BoxPainter.h"
 #include "core/paint/PaintInfo.h"
 #include "core/style/BorderEdge.h"
@@ skipping 239 matching lines @@
         -edges[BSBottom].getDoubleBorderStripeWidth(stripe),
         -edges[BSLeft].getDoubleBorderStripeWidth(stripe));
 }
 
 void drawSolidBorderRect(GraphicsContext* context, const FloatRect& borderRect,
     float borderWidth, const Color& color)
 {
     FloatRect strokeRect(borderRect);
     strokeRect.inflate(-borderWidth / 2);
 
-    bool antialias = BoxPainter::shouldAntialiasLines(context);
     bool wasAntialias = context->shouldAntialias();
-    if (antialias != wasAntialias)
-        context->setShouldAntialias(antialias);
+    if (!wasAntialias)
+        context->setShouldAntialias(true);
 
     context->setStrokeStyle(SolidStroke);
     context->setStrokeColor(color);
     context->strokeRect(strokeRect, borderWidth);
 
-    if (antialias != wasAntialias)
-        context->setShouldAntialias(wasAntialias);
+    if (!wasAntialias)
+        context->setShouldAntialias(false);
 }
 
 void drawBleedAdjustedDRRect(GraphicsContext* context, BackgroundBleedAvoidance bleedAvoidance,
     const FloatRoundedRect& outer, const FloatRoundedRect& inner, Color color)
 {
     switch (bleedAvoidance) {
     case BackgroundBleedBackgroundOverBorder:
         // BackgroundBleedBackgroundOverBorder draws an opaque background over the inner rrect,
         // so we can simply fill the outer rect here to avoid backdrop bleeding.
         context->fillRoundedRect(outer, color);
@@ skipping 907 matching lines @@
         FloatPoint secondQuad[4];
         secondQuad[0] = quad[0];
         secondQuad[1] = FloatPoint(quad[0].x() - r1 * cx, quad[0].y() - r1 * cy);
         secondQuad[2] = quad[2];
         secondQuad[3] = quad[3];
         graphicsContext->clipPolygon(4, secondQuad, secondMiter == SoftMiter);
     }
 }
 
 } // namespace blink