Minor code cleanup (left over from prior CL)

gm/matrixconvolution.cpp

Index: gm/matrixconvolution.cpp
diff --git a/gm/matrixconvolution.cpp b/gm/matrixconvolution.cpp
index 1e6a49d4b6b480c80a07bce7afb33cfc29b9c9dc..6d16f8dfa74df4f5e92a93c176f8e527a1375f67 100644
--- a/gm/matrixconvolution.cpp
+++ b/gm/matrixconvolution.cpp
@@ -14,17 +14,17 @@ namespace skiagm {
 
 class MatrixConvolutionGM : public GM {
 public:
-    MatrixConvolutionGM() : fInitialized(false) {
+    MatrixConvolutionGM() {
         this->setBGColor(0x00000000);
     }
 
 protected:
 
-    virtual SkString onShortName() {
+    SkString onShortName() override {
         return SkString("matrixconvolution");
     }
 
-    void make_bitmap() {
+    void makeBitmap() {
         fBitmap.allocN32Pixels(80, 80);
         SkCanvas canvas(fBitmap);
         canvas.clear(0x00000000);
@@ -43,7 +43,7 @@ protected:
         canvas.drawText(str, strlen(str), SkIntToScalar(-10), SkIntToScalar(80), paint);
     }
 
-    virtual SkISize onISize() {
+    SkISize onISize() override {
         return SkISize::Make(500, 300);
     }
 
@@ -79,11 +79,11 @@ protected:
 
     typedef SkMatrixConvolutionImageFilter MCIF;
 
-    virtual void onDraw(SkCanvas* canvas) {
-        if (!fInitialized) {
-            make_bitmap();
-            fInitialized = true;
-        }
+    void onOnceBeforeDraw() override {
+        this->makeBitmap();
+    }
+
+    void onDraw(SkCanvas* canvas) override {
         canvas->clear(SK_ColorBLACK);
         SkIPoint kernelOffset = SkIPoint::Make(1, 0);
         for (int x = 10; x < 310; x += 100) {
@@ -104,14 +104,13 @@ protected:
     }
 
 private:
-    typedef GM INHERITED;
     SkBitmap fBitmap;
-    bool fInitialized;
+
+    typedef GM INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
-static GM* MyFactory(void*) { return new MatrixConvolutionGM; }
-static GMRegistry reg(MyFactory);
+DEF_GM(return new MatrixConvolutionGM;)
 
 }