Bug fix for cull_line in SkDashPathEffect.

gm/dashing.cpp

 /*
  * Copyright 2012 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 "SkPaint.h"
@@ skipping 16 matching lines @@
 
 // earlier bug stopped us from drawing very long single-segment dashes, because
 // SkPathMeasure was skipping very small delta-T values (nearlyzero). This is
 // now fixes, so this giant dash should appear.
 static void show_giant_dash(SkCanvas* canvas) {
     SkPaint paint;
 
     drawline(canvas, 1, 1, paint, SkIntToScalar(20 * 1000));
 }
 
+static void show_zero_len_dash(SkCanvas* canvas) {
+    SkPaint paint;
+
+    drawline(canvas, 2, 2, paint, SkIntToScalar(0));
+    paint.setStyle(SkPaint::kStroke_Style);
+    paint.setStrokeWidth(SkIntToScalar(2));
+    canvas->translate(0, SkIntToScalar(20));
+    drawline(canvas, 4, 4, paint, SkIntToScalar(0));
+}
+
 class DashingGM : public skiagm::GM {
 public:
     DashingGM() {}
 
 protected:
     virtual uint32_t onGetFlags() const SK_OVERRIDE {
         return kSkipTiled_Flag;
     }
 
     SkString onShortName() {
@@ skipping 27 matching lines @@
 
                     drawline(canvas, gData[data].fOnInterval * scale,
                              gData[data].fOffInterval * scale,
                              paint);
                     canvas->translate(0, SkIntToScalar(20));
                 }
             }
         }
 
         show_giant_dash(canvas);
+        canvas->translate(0, SkIntToScalar(20));
+        show_zero_len_dash(canvas);
     }
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 static void make_unit_star(SkPath* path, int n) {
     SkScalar rad = -SK_ScalarPI / 2;
     const SkScalar drad = (n >> 1) * SK_ScalarPI * 2 / n;
 
     path->moveTo(0, -SK_Scalar1);
@@ skipping 379 matching lines @@
 
 //////////////////////////////////////////////////////////////////////////////
 
 DEF_GM(return SkNEW(DashingGM);)
 DEF_GM(return SkNEW(Dashing2GM);)
 DEF_GM(return SkNEW(Dashing3GM);)
 DEF_GM(return SkNEW(Dashing4GM);)
 DEF_GM(return SkNEW_ARGS(Dashing5GM, (true));)
 DEF_GM(return SkNEW_ARGS(Dashing5GM, (false));)