Add BUILD.gn for third_party/freetype

BUILD.gn

+# Copyright 2014 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.
+
+assert(is_android, "This library is only used on Android")
+
+config("freetype_config") {
+  include_dirs = [ "include" ]
+}
+
+source_set("freetype") {
+  sources = [
+    # The following files are not sorted alphabetically, but in the
+    # same order as in Android.mk to ease maintenance.
+    "src/base/ftbbox.c",
+    "src/base/ftbitmap.c",
+    "src/base/ftfstype.c",
+    "src/base/ftglyph.c",
+    "src/base/ftlcdfil.c",
+    "src/base/ftstroke.c",
+    "src/base/fttype1.c",
+    "src/base/ftxf86.c",
+    "src/base/ftbase.c",
+    "src/base/ftsystem.c",
+    "src/base/ftinit.c",
+    "src/base/ftgasp.c",
+    "src/base/ftmm.c",
+    "src/gzip/ftgzip.c",
+    "src/raster/raster.c",
+    "src/sfnt/sfnt.c",
+    "src/smooth/smooth.c",
+    "src/autofit/autofit.c",
+    "src/truetype/truetype.c",
+    "src/cff/cff.c",
+    "src/psnames/psnames.c",
+    "src/pshinter/pshinter.c",
+  ]
+
+  defines = [
+    "FT2_BUILD_LIBRARY",
+    "DARWIN_NO_CARBON",
+  ]
+
+  include_dirs = [ "build" ]

[Xianzhu, 2015/06/02 18:38:46]

There seems an error in freetype.gyp about 'build' which should be 'builds'.
However because we never used the include dir, I think we can remove this rule
(as well as the rule in freetype.gyp).

[bungeman-chromium, 2015/06/02 19:10:24]

hmmm... yes I had wondered about that. Apparently the one include in the
'builds' directory is designed around installing, which we never do. I'll remove
it.

+
+  public_configs = [ ":freetype_config" ]
+
+  deps = [
+    "//third_party/libpng",
+    "//third_party/zlib",
+  ]
+}