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/SampleXfermodesBlur.cpp b/samplecode/SampleXfermodesBlur.cpp
index 592cf71..b565b79 100644
--- a/samplecode/SampleXfermodesBlur.cpp
+++ b/samplecode/SampleXfermodesBlur.cpp
@@ -73,9 +73,9 @@
     }
 
 protected:
-    virtual SkString name() { return SkString("XfermodesBlur"); }
+    SkString name() override { return SkString("XfermodesBlur"); }
 
-    virtual void onDrawContent(SkCanvas* canvas) {
+    void onDrawContent(SkCanvas* canvas) override {
         canvas->translate(SkIntToScalar(10), SkIntToScalar(20));
 
         const SkBlendMode gModes[] = {