Samples: clean up cruft

  - replace virtual with override.
  - remove default constructor.
  - use default field initializers
  - move work from constructor into onOnceBeforeDraw
  - mark everything private
  - enum { N = 100 }; constants to constexpr
  - remove unused variables

Change-Id: I8c7a19bc24fec416a6b88d634ee948d3e842b986
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/228056
Commit-Queue: Ben Wagner <bungeman@google.com>
Auto-Submit: Hal Canary <halcanary@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
diff --git a/samplecode/SampleClipDrawMatch.cpp b/samplecode/SampleClipDrawMatch.cpp
index 729e16a..bdbb54b 100644
--- a/samplecode/SampleClipDrawMatch.cpp
+++ b/samplecode/SampleClipDrawMatch.cpp
@@ -115,8 +115,17 @@
 }
 
 class ClipDrawMatchView : public Sample {
+    SkInterpolator  fTrans;
+    Geometry        fGeom;
+    bool            fClipFirst = true;
+    int             fSign = 1;
+    const double    fStart = SkTime::GetMSecs();
+
 public:
-    ClipDrawMatchView() : fTrans(2, 5), fGeom(kRect_Geometry), fClipFirst(true), fSign(1) {
+    ClipDrawMatchView() : fTrans(2, 5), fGeom(kRect_Geometry) {}
+
+private:
+    void onOnceBeforeDraw() override {
         SkScalar values[2];
 
         fTrans.setRepeatCount(999);
@@ -132,7 +141,6 @@
         fTrans.setKeyFrame(4, GetMSecs() + 5000, values);
     }
 
-protected:
     SkString name() override { return SkString("ClipDrawMatch"); }
 
     bool onChar(SkUnichar uni) override {
@@ -239,17 +247,6 @@
     SkMSec GetMSecs() const {
         return static_cast<SkMSec>(SkTime::GetMSecs() - fStart);
     }
-
-private:
-    SkInterpolator  fTrans;
-    Geometry        fGeom;
-    bool            fClipFirst;
-    int             fSign;
-    const double    fStart = SkTime::GetMSecs();
-
-    typedef Sample INHERITED;
 };
 
-//////////////////////////////////////////////////////////////////////////////
-
 DEF_SAMPLE( return new ClipDrawMatchView(); )