Fix up -Winconsistent-missing-override

src/core/SkFunction.h

Index: src/core/SkFunction.h
diff --git a/src/core/SkFunction.h b/src/core/SkFunction.h
index 429c6f5ade327543e62a92b72296c4809179545e..8e41cba929a08b4303247f5f1b51474ae2244d66 100644
--- a/src/core/SkFunction.h
+++ b/src/core/SkFunction.h
@@ -54,7 +54,7 @@ private:
         LambdaImpl(const Fn& fn) : fFn(fn) {}
 
         R call(Args... args) const override { return fFn(Forward(args)...); }
-        Interface* clone() const { return SkNEW_ARGS(LambdaImpl<Fn>, (fFn)); }
+        Interface* clone() const override { return SkNEW_ARGS(LambdaImpl<Fn>, (fFn)); }
     private:
         Fn fFn;
     };
@@ -64,7 +64,7 @@ private:
         FnPtrImpl(R (*fn)(Args...)) : fFn(fn) {}
 
         R call(Args... args) const override { return fFn(Forward(args)...); }
-        Interface* clone() const { return SkNEW_ARGS(FnPtrImpl, (fFn)); }
+        Interface* clone() const override { return SkNEW_ARGS(FnPtrImpl, (fFn)); }
     private:
         R (*fFn)(Args...);
     };