fix hairline clip

gm/bug5252.cpp

+/*
+* Copyright 2016 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 "SkRect.h"
+#include "SkPath.h"
+
+DEF_SIMPLE_GM(bug5252, canvas, 500, 500) {
+        canvas->translate(SkIntToScalar(10), SkIntToScalar(20));
+
+        SkPath clip1;
+        clip1.addOval(SkRect::MakeWH(225, 200));
+        canvas->clipPath(clip1); // bug
+
+        SkPath clip2;
+        clip2.addRect(SkRect::MakeWH(220, 200));
+        //canvas->clipPath(clip2); // ok
+
+        SkPaint pa;
+        pa.setStyle(SkPaint::kStroke_Style);
+        pa.setAntiAlias(true);
+        pa.setStrokeWidth(1.0f);
+        for (int i = 0; i < 15; i++)
+        {
+                for (int j = 0; j < 10; j++)
+                {
+                        SkAutoCanvasRestore acs(canvas, true);
+
+                        canvas->translate(i * 15.f, j * 20.f);
+                        canvas->drawRect(SkRect::MakeXYWH(5, 5, 10, 15),pa);
+                        SkPath path;
+                        path.moveTo(6, 6);
+                        path.cubicTo(14, 10, 13, 12, 10, 12);
+                        path.cubicTo(7, 15, 8, 17, 14, 18);
+                        canvas->drawPath(path, pa);
+                }
+        }
+}