[sksg] Stop caching full SkPaints in Paint nodes

Create on the fly, when needed.

TBR=
Bug: skia:8340
Change-Id: I4c319821a6d6e84e0ec37e8858c4a89ba1668626
Reviewed-on: https://skia-review.googlesource.com/153141
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
diff --git a/modules/sksg/include/SkSGPaintNode.h b/modules/sksg/include/SkSGPaintNode.h
index 5c9563b..dc4af49 100644
--- a/modules/sksg/include/SkSGPaintNode.h
+++ b/modules/sksg/include/SkSGPaintNode.h
@@ -22,7 +22,7 @@
  */
 class PaintNode : public Node {
 public:
-    const SkPaint& makePaint();
+    SkPaint makePaint() const;
 
     SG_ATTRIBUTE(AntiAlias  , bool          , fAntiAlias  )
     SG_ATTRIBUTE(Opacity    , SkScalar      , fOpacity    )
@@ -41,8 +41,6 @@
     SkRect onRevalidate(InvalidationController*, const SkMatrix&) final;
 
 private:
-    SkPaint        fPaint;
-
     SkScalar       fOpacity     = 1,
                    fStrokeWidth = 1,
                    fStrokeMiter = 4;