tools/SkShaper: factor shaping out of using_skia_and_harfbuzz

tools/SkShaper.h

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkShaper_DEFINED
+#define SkShaper_DEFINED
+
+#include <memory>
+
+#include "SkPoint.h"
+#include "SkTypeface.h"
+
+class SkPaint;
+class SkTextBlobBuilder;
+
+/**
+   Shapes text using harfbuzz and places the shaped text into a
+   TextBlob.
+ */
+class SkShaper {
+public:
+    SkShaper(sk_sp<SkTypeface> face);
+    ~SkShaper();
+
+    bool good() const;
+    SkScalar shape(SkTextBlobBuilder* dest,
+                   const SkPaint& srcPaint,
+                   const char* utf8text,
+                   size_t textBytes,
+                   SkPoint point) const;
+
+private:
+    SkShaper(const SkShaper&) = delete;
+    SkShaper& operator=(const SkShaper&) = delete;
+
+    struct Impl;
+    std::unique_ptr<Impl> fImpl;
+};
+
+#endif  // SkShaper_DEFINED