remove fun operator overloads

Change-Id: I6ae2d5d1cbe2fc5d9d782aa96900acd5703080e9
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/265757
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/samplecode/Sample3D.cpp b/samplecode/Sample3D.cpp
index 4478386..cc2fa5b 100644
--- a/samplecode/Sample3D.cpp
+++ b/samplecode/Sample3D.cpp
@@ -166,7 +166,7 @@
 static SkColorMatrix comput_planar_lighting(SkCanvas* canvas, SkV3 lightDir) {
     SkM44 l2w = canvas->experimental_getLocalToWorld();
     auto normal = normalize(l2w * SkV3{0, 0, 1});
-    float dot = -normal * lightDir;
+    float dot = -normal.dot(lightDir);
 
     SkColorMatrix cm;
     if (dot < 0) {