refactor gyp to isolate freetype usage

gyp/core.gyp

 # Core Skia library code.
 {
   'targets': [
     {
       'target_name': 'core',
       'product_name': 'skia_core',
       'type': 'static_library',
       'standalone_static_library': 1,
       'msvs_guid': 'B7760B5E-BFA8-486B-ACFD-49E3A6DE8E76',
 
@@ skipping 21 matching lines @@
         [ 'skia_os in ["linux", "freebsd", "openbsd", "solaris", "chromeos"]', {
           'link_settings': {
             'libraries': [
               '-lpthread',
             ],
           },
         }],
         [ 'skia_os == "mac"', {
           'include_dirs': [
             '../include/utils/mac',
-            '../third_party/freetype/include/**',
           ],
           'sources': [
             '../include/utils/mac/SkCGUtils.h',
           ],
           'link_settings': {
             'libraries': [
               '$(SDKROOT)/System/Library/Frameworks/ApplicationServices.framework',
             ],
           },
         }],
@@ skipping 50 matching lines @@
           '../include/core',
           '../include/lazy',
           '../include/pathops',
           '../include/pipe',
           'ext',
         ],
         'conditions': [
           [ 'skia_os == "mac"', {
             'include_dirs': [
               '../include/utils/mac',
-              '../third_party/freetype/include/**',
             ],
           }],
           [ 'skia_os == "ios"', {
             'include_dirs': [
               '../include/utils/ios',
             ],
           }],
           [ 'skia_os == "win"', {
             'include_dirs': [
               'config/win',
             ],
           }],
         ],
       },
     },
   ],
 }
 
 # Local Variables:
 # tab-width:2
 # indent-tabs-mode:nil
 # End:
 # vim: set expandtab tabstop=2 shiftwidth=2: