Add implementation of path ops

src/pathops/SkPathWriter.h

+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#ifndef SkPathWriter_DEFINED
+#define SkPathWriter_DEFINED
+
+#include "SkPath.h"
+
+class SkPathWriter {
+public:
+    SkPathWriter(SkPath& path);
+    void close();
+    void cubicTo(const SkPoint& pt1, const SkPoint& pt2, const SkPoint& pt3);
+    void deferredLine(const SkPoint& pt);
+    void deferredMove(const SkPoint& pt);
+    void deferredMoveLine(const SkPoint& pt);
+    bool hasMove() const;
+    void init();
+    bool isClosed() const;
+    void lineTo();
+    const SkPath* nativePath() const;
+    void nudge();
+    void quadTo(const SkPoint& pt1, const SkPoint& pt2);
+    bool someAssemblyRequired() const;
+    
+private:
+    bool changedSlopes(const SkPoint& pt) const;
+    void moveTo();
+    
+    SkPath* fPathPtr;
+    SkPoint fDefer[2];
+    SkPoint fFirstPt;
+    int fCloses;
+    int fMoves;
+    bool fEmpty;
+    bool fHasMove;
+    bool fMoved;
+};
+
+
+#endif /* defined(__PathOps__SkPathWriter__) */