Fix clang 12 Wsuggest-override and Wsuggest-destructor-override


Change-Id: Ic44e24057b95bb014504f02a736fb4341afc8971
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/304856
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
diff --git a/samplecode/SampleAAGeometry.cpp b/samplecode/SampleAAGeometry.cpp
index 8eb82b9..b500785 100644
--- a/samplecode/SampleAAGeometry.cpp
+++ b/samplecode/SampleAAGeometry.cpp
@@ -541,9 +541,7 @@
         ,  fValHi(fMax) {
     }
 
-    virtual ~BiControl() {}
-
-    virtual void draw(SkCanvas* canvas, const ControlPaints& paints) {
+    void draw(SkCanvas* canvas, const ControlPaints& paints) override {
         UniControl::draw(canvas, paints);
         if (!fVisible || fValHi == fValLo) {
             return;