fix teeny dashed path bug

tests/DashPathEffectTest.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Test.h"
 
 #include "SkDashPathEffect.h"
@@ skipping 69 matching lines @@
                 if (i < 2) {
                     REPORTER_ASSERT(r, actualResult == testCases[j].fExpectedResult);
                 } else {
                     // On the third pass all the lines should be outside the translated cull rect
                     REPORTER_ASSERT(r, !actualResult);
                 }
             }
         }
     }
 }
+
+DEF_TEST(DashPath_bug4871, r) {
+    SkPath path;
+    path.moveTo(30, 24);
+    path.cubicTo(30.002f, 24, 30, 24, 30, 24);
+    path.close();
+
+    SkScalar intervals[2] = { 1, 1 };
+    SkAutoTUnref<SkPathEffect> dash(SkDashPathEffect::Create(intervals, 2, 0));
+
+    SkPaint paint;
+    paint.setStyle(SkPaint::kStroke_Style);
+    paint.setPathEffect(dash);
+
+    SkPath fill;
+    paint.getFillPath(path, &fill);
+}