Create blink_headers target for header-only dependencies

public/blink.gyp

 #
 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #         * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #         * Redistributions in binary form must reproduce the above
@@ skipping 21 matching lines @@
         '../Source/build/features.gypi',
     ],
     'targets': [
         {
             'target_name': 'blink',
             'type': 'none',
             'dependencies': [
                 '../Source/web/web.gyp:blink_web',
                 '../Source/platform/blink_platform.gyp:blink_platform',
                 'blink_minimal',
+                'blink_headers',
             ],
             'export_dependent_settings': [
                 '../Source/web/web.gyp:blink_web',
                 '../Source/platform/blink_platform.gyp:blink_platform',
                 'blink_minimal',
             ],
         },
         {
+          # Depend on this target to use public blink API headers for things
+          # like enums and public structures without actually linking against any Blink
+          # libraries.
+          'target_name': 'blink_headers',
+          'type': 'none',
+          'direct_dependent_settings': {
+            'include_dirs': [ '..' ],
+          },
+        },
+        {
             # This target provides a minimal set of Blink APIs such as WebString to use in
             # places that cannot link against the full Blink library.
             # FIXME: We really shouldn't have this at all and should instead remove all uses
             # of Blink's API types from places that can't link against Blink. crbug.com/248653
             'target_name': 'blink_minimal',
             'type': 'none',
             'dependencies': [
                 '../Source/platform/blink_platform.gyp:blink_common',
             ],
             'export_dependent_settings': [
@@ skipping 15 matching lines @@
             'type': 'none',
             'dependencies': [
                 'blink_test_support',
             ],
             'export_dependent_settings': [
                 'blink_test_support',
             ],
         },
     ],
 }