Add sfntly library for font subsetting used in print preview.

third_party/sfntly/src/subsetter/subsetter_impl.h

+/*
+ * Copyright 2011 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SUBSETTER_IMPL_H_
+#define SUBSETTER_IMPL_H_
+
+#include "sfntly/font.h"
+#include "sfntly/font_factory.h"
+
+namespace sfntly {
+
+class SubsetterImpl : public RefCounted<SubsetterImpl> {
+ public:
+  SubsetterImpl();
+  ~SubsetterImpl();
+
+  bool loadFont(const char* font_name,
+                const unsigned char* original_font,
+                const size_t font_size);
+  int subsetFont(const unsigned int* glyph_ids,
+                 const size_t glyph_count,
+                 unsigned char** output_buffer);
+
+ private:
+  Font* findFont(const char* font_name, FontArray& font_array);
+  bool hasName(const char* font_name, Font* font);
+  CALLER_ATTACH Font* subset(const unsigned int* glyph_ids,

[Sheridan Rawlins, 2011/07/14 22:35:51]

Can this be forward declared instead of included?

Also,  What's the memory contract for this return value?  Can you write more
documentation?

[arthurhsu, 2011/07/14 23:52:35]

It accesses data member and has to be a member function.
Added comments regarding memory contracts.

+                             const size_t glyph_count);
+
+  FontFactoryPtr factory_;
+  FontPtr font_;
+};
+
+}
+
+#endif  // SUBSETTER_IMPL_H_