allow one zero length dash

gm/arcto.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 #include "SkParsePath.h"
 #include "SkPath.h"
@@ skipping 187 matching lines @@
     SkRect oval = SkRect::MakeXYWH(-radius, yOffset - radius, 2 * radius, 2 * radius);
     p.arcTo(oval, 1.25f * 180, .5f * 180, false);
 
     SkPaint paint;
     paint.setStyle(SkPaint::kStroke_Style);
     paint.setStrokeCap(SkPaint::kRound_Cap);
     paint.setStrokeWidth(15.36f);
 
     canvas->drawPath(p, paint);
 }
+
+#include "SkDashPathEffect.h"
+#include "SkPathMeasure.h"
+
+DEF_SIMPLE_GM(bug583299, canvas, 300, 300) {
+  const char* d="M60,60 A50,50 0 0 0 160,60 A50,50 0 0 0 60,60z";
+  SkPaint p;
+  p.setStyle(SkPaint::kStroke_Style);
+  p.setStrokeWidth(100);
+  p.setAntiAlias(true);
+  p.setColor(0xFF008200);
+  p.setStrokeCap(SkPaint::kSquare_Cap);
+  SkPath path;
+  SkParsePath::FromSVGString(d, &path);
+  SkPathMeasure meas(path, false);
+  SkScalar length = meas.getLength();
+  SkScalar intervals[] = {0, length };
+  int intervalCount = (int) SK_ARRAY_COUNT(intervals);
+  p.setPathEffect(SkDashPathEffect::Create(intervals, intervalCount, 0))->unref();
+  canvas->drawPath(path, p);
+}