Update from https://crrev.com/317530

third_party/ots/src/ltsh.cc

Index: third_party/ots/src/ltsh.cc
diff --git a/third_party/ots/src/ltsh.cc b/third_party/ots/src/ltsh.cc
new file mode 100644
index 0000000000000000000000000000000000000000..418c1598e43237a249003cd9c3fad64c4112ad02
--- /dev/null
+++ b/third_party/ots/src/ltsh.cc
@@ -0,0 +1,92 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ltsh.h"
+
+#include "maxp.h"
+
+// LTSH - Linear Threshold
+// http://www.microsoft.com/typography/otspec/ltsh.htm
+
+#define TABLE_NAME "LTSH"
+
+#define DROP_THIS_TABLE(...) \
+  do { \
+    OTS_FAILURE_MSG_(file, TABLE_NAME ": " __VA_ARGS__); \
+    OTS_FAILURE_MSG("Table discarded"); \
+    delete file->ltsh; \
+    file->ltsh = 0; \
+  } while (0)
+
+namespace ots {
+
+bool ots_ltsh_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
+  Buffer table(data, length);
+
+  if (!file->maxp) {
+    return OTS_FAILURE_MSG("Missing maxp table from font needed by ltsh");
+  }
+
+  OpenTypeLTSH *ltsh = new OpenTypeLTSH;
+  file->ltsh = ltsh;
+
+  uint16_t num_glyphs = 0;
+  if (!table.ReadU16(&ltsh->version) ||
+      !table.ReadU16(&num_glyphs)) {
+    return OTS_FAILURE_MSG("Failed to read ltsh header");
+  }
+
+  if (ltsh->version != 0) {
+    DROP_THIS_TABLE("bad version: %u", ltsh->version);
+    return true;
+  }
+
+  if (num_glyphs != file->maxp->num_glyphs) {
+    DROP_THIS_TABLE("bad num_glyphs: %u", num_glyphs);
+    return true;
+  }
+
+  ltsh->ypels.reserve(num_glyphs);
+  for (unsigned i = 0; i < num_glyphs; ++i) {
+    uint8_t pel = 0;
+    if (!table.ReadU8(&pel)) {
+      return OTS_FAILURE_MSG("Failed to read pixels for glyph %d", i);
+    }
+    ltsh->ypels.push_back(pel);
+  }
+
+  return true;
+}
+
+bool ots_ltsh_should_serialise(OpenTypeFile *file) {
+  if (!file->glyf) return false;  // this table is not for CFF fonts.
+  return file->ltsh != NULL;
+}
+
+bool ots_ltsh_serialise(OTSStream *out, OpenTypeFile *file) {
+  const OpenTypeLTSH *ltsh = file->ltsh;
+
+  const uint16_t num_ypels = static_cast<uint16_t>(ltsh->ypels.size());
+  if (num_ypels != ltsh->ypels.size() ||
+      !out->WriteU16(ltsh->version) ||
+      !out->WriteU16(num_ypels)) {
+    return OTS_FAILURE_MSG("Failed to write pels size");
+  }
+  for (uint16_t i = 0; i < num_ypels; ++i) {
+    if (!out->Write(&(ltsh->ypels[i]), 1)) {
+      return OTS_FAILURE_MSG("Failed to write pixel size for glyph %d", i);
+    }
+  }
+
+  return true;
+}
+
+void ots_ltsh_free(OpenTypeFile *file) {
+  delete file->ltsh;
+}
+
+}  // namespace ots
+
+#undef TABLE_NAME
+#undef DROP_THIS_TABLE