Add copyright headers to remaining gyp files.

gyp/freetype.gyp

+# Copyright 2015 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
 # Target for building freetype.
 {
   'targets': [
     {
       'target_name': 'freetype',
       'type': 'none',
       'conditions': [
         [ 'skia_freetype_static',
           {
             'dependencies': [
@@ skipping 92 matching lines @@
             '-DPIC',
             '-DDARWIN_NO_CARBON',
             '-DFT2_BUILD_LIBRARY',
             '-O2',
           ],
         }],
       ],
     },
   ],
 }