Make skia compile in Android GN build.

tools/gn/secondary/third_party/freetype/BUILD.gn

Index: tools/gn/secondary/third_party/freetype/BUILD.gn
diff --git a/tools/gn/secondary/third_party/freetype/BUILD.gn b/tools/gn/secondary/third_party/freetype/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..ee70c4e89cfbccd35ee207b42134aa180afb06dc
--- /dev/null
+++ b/tools/gn/secondary/third_party/freetype/BUILD.gn
@@ -0,0 +1,52 @@
+# 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/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",
+  ]
+
+  direct_dependent_configs = [ ":freetype_config" ]
+
+  deps = [
+    "//third_party/libpng",
+    "//third_party/zlib",
+  ]
+}