GM: replace boilerplate with macros

gm/stroketext.cpp

Index: gm/stroketext.cpp
diff --git a/gm/stroketext.cpp b/gm/stroketext.cpp
index 75ce164bcf733fed37cf96d6896a96dd5df18986..d0a9882256ba5a12fb0cb0badd3bd91a63a57eb7 100644
--- a/gm/stroketext.cpp
+++ b/gm/stroketext.cpp
@@ -59,28 +59,14 @@ static void draw_text_set(SkCanvas* canvas, const SkPaint& paint) {
     draw_text_stroked(canvas, p, 10);
 }
 
-class StrokeTextGM : public skiagm::GM {
-    // Skia has a threshold above which it draws text via paths instead of using scalercontext
-    // and caching the glyph. This GM wants to ensure that we draw stroking correctly on both
-    // sides of this threshold.
+namespace {
     enum {
         kBelowThreshold_TextSize = 255,
         kAboveThreshold_TextSize = 257
     };
-public:
-    StrokeTextGM() {}
-
-protected:
-
-    SkString onShortName() override {
-        return SkString("stroketext");
-    }
-
-    SkISize onISize() override {
-        return SkISize::Make(1200, 480);
-    }
+}
 
-    void onDraw(SkCanvas* canvas) override {
+DEF_SIMPLE_GM(stroketext, canvas, 1200, 480) {
         if (true) { test_nulldev(canvas); }
         SkPaint paint;
         paint.setAntiAlias(true);
@@ -92,10 +78,4 @@ protected:
         canvas->translate(600, 0);
         paint.setTextSize(kAboveThreshold_TextSize);
         draw_text_set(canvas, paint);
-    }
-
-private:
-    typedef skiagm::GM INHERITED;
-};
-
-DEF_GM(return new StrokeTextGM;)
+}