Build FreeType with HarfBuzz support

third_party/harfbuzz-ng/harfbuzz.gni

+# Copyright 2017 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.
+
+declare_args() {
+  # Blink uses a cutting-edge version of Harfbuzz; most Linux distros do not
+  # contain a new enough version of the code to work correctly. However,
+  # ChromeOS chroots (i.e, real ChromeOS builds for devices) do contain a
+  # new enough version of the library, and so this variable exists so that
+  # ChromeOS can build against the system lib and keep binary sizes smaller.
+  use_system_harfbuzz = false
+}