Add copyright headers to remaining gyp files.

gyp/freetype.gypi

+# Copyright 2015 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
 {
   'sources': [
     # base components (required)
     '../third_party/externals/freetype/src/base/ftsystem.c',
     '../third_party/externals/freetype/src/base/ftinit.c',
     '../third_party/externals/freetype/src/base/ftdebug.c',
     '../third_party/externals/freetype/src/base/ftbase.c',
 
     '../third_party/externals/freetype/src/base/ftbbox.c',       # recommended, see <freetype/ftbbox.h>
     '../third_party/externals/freetype/src/base/ftglyph.c',      # recommended, see <freetype/ftglyph.h>
@@ skipping 44 matching lines @@
         '../third_party/externals/freetype/src/base/ftmac.c',        # only on the Macintosh
       ],
     }],
   ],
   'direct_dependent_settings': {
     'include_dirs': [
       '../third_party/externals/freetype/include',
     ],
   },
 }