add new gm for SkPath::addArc()

gm/addarc.cpp

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+#include "SkCanvas.h"
+#include "SkRandom.h"
+
+class AddArcGM : public skiagm::GM {
+protected:
+    SkString onShortName() SK_OVERRIDE { return SkString("addarc"); }
+
+    SkISize onISize() SK_OVERRIDE { return SkISize::Make(1040, 1040); }
+
+    void onDraw(SkCanvas* canvas) SK_OVERRIDE {
+        canvas->translate(20, 20);
+
+        SkRect r = SkRect::MakeWH(1000, 1000);
+
+        SkPaint paint;
+        paint.setAntiAlias(true);
+        paint.setStyle(SkPaint::kStroke_Style);
+        paint.setStrokeWidth(15);
+
+        const SkScalar inset = paint.getStrokeWidth() + 4;
+        const SkScalar sweepAngle = 345;
+        SkRandom rand;
+
+        while (r.width() > paint.getStrokeWidth() * 3) {
+            paint.setColor(rand.nextU() | (0xFF << 24));
+            SkScalar startAngle = rand.nextUScalar1() * 360;
+
+            SkPath path;
+            path.addArc(r, startAngle, sweepAngle);
+            canvas->drawPath(path, paint);
+
+            r.inset(inset, inset);
+
+        }
+    }
+
+private:
+    typedef skiagm::GM INHERITED;
+};
+DEF_GM( return new AddArcGM; )