SP: Always anti-alias borders in slimming paint mode.

Source/core/paint/BoxPainter.cpp

Index: Source/core/paint/BoxPainter.cpp
diff --git a/Source/core/paint/BoxPainter.cpp b/Source/core/paint/BoxPainter.cpp
index 160934f6c864c0aa4a631263a67ee4fc20b294f3..a6f6801b296be74991781ca6114ff2e79b714eee 100644
--- a/Source/core/paint/BoxPainter.cpp
+++ b/Source/core/paint/BoxPainter.cpp
@@ -873,6 +873,8 @@ bool BoxPainter::paintNinePieceImage(LayoutBoxModelObject& obj, GraphicsContext*
 
 bool BoxPainter::shouldAntialiasLines(GraphicsContext* context)
 {
+    if (RuntimeEnabledFeatures::slimmingPaintEnabled())
+        return true;
     // FIXME: We may want to not antialias when scaled by an integral value,
     // and we may want to antialias when translated by a non-integral value.
     // FIXME: See crbug.com/382491. getCTM does not include scale factors applied at raster time, such