add std::function option to Click to simplify callsites

More sites to update, but can happen later

Change-Id: I75e8b60050c6af2a1563057f7fe9da84bc017370
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/284876
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Reed <reed@google.com>
diff --git a/samplecode/SamplePathClip.cpp b/samplecode/SamplePathClip.cpp
index c7852ab..daf5bb3 100644
--- a/samplecode/SamplePathClip.cpp
+++ b/samplecode/SamplePathClip.cpp
@@ -53,12 +53,10 @@
     }
 
     Sample::Click* onFindClickHandler(SkScalar x, SkScalar y, skui::ModifierKey) override {
-        return new Click();
-    }
-
-    bool onClick(Click* click) override {
-        fCenter.set(click->fCurr.fX, click->fCurr.fY);
-        return false;
+        return new Click([&](Click* c) {
+            fCenter = c->fCurr;
+            return false;
+        });
     }
 
 private: