Add sfntly library for font subsetting used in print preview.

third_party/sfntly/src/subsetter/font_subsetter.cc

+/*
+ * 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.
+ */
+
+#include "third_party/sfntly/src/subsetter/font_subsetter.h"
+
+#include "third_party/sfntly/src/subsetter/subsetter_impl.h"
+
+int SfntlyWrapper::SubsetFont(const char* font_name,
+                              const unsigned char* original_font,
+                              size_t font_size,
+                              const unsigned int* glyph_ids,
+                              size_t glyph_count,
+                              unsigned char** output_buffer) {
+  if (output_buffer == NULL ||
+      original_font == NULL || font_size == 0 ||
+      glyph_ids == NULL || glyph_count == 0) {
+    return 0;
+  }
+
+  sfntly::SubsetterImpl subsetter;
+  if (!subsetter.LoadFont(font_name, original_font, font_size)) {
+    return -1;  // Load error or font not found.
+  }
+
+  return subsetter.SubsetFont(glyph_ids, glyph_count, output_buffer);
+}