add missing SK_OVERRIDE

src/core/SkPicturePreroll.cpp

Index: src/core/SkPicturePreroll.cpp
diff --git a/src/core/SkPicturePreroll.cpp b/src/core/SkPicturePreroll.cpp
index b0a4b17f56c71441fa2bd3c462ac6423082cccc2..c2d10fc7a28d975aee61b7512afa1c7eb31f0e68 100644
--- a/src/core/SkPicturePreroll.cpp
+++ b/src/core/SkPicturePreroll.cpp
@@ -62,7 +62,7 @@ protected:
         this->handlePaint(paint);
     }
 
-    void onDrawPoints(PointMode, size_t, const SkPoint[], const SkPaint& paint) {
+    void onDrawPoints(PointMode, size_t, const SkPoint[], const SkPaint& paint) SK_OVERRIDE {
         this->handlePaint(paint);
     }