Add some src/webkit build files to the GN build.

webkit/webkit_resources.gyp

 # Copyright 2013 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.
 
 {
   'targets': [
     {
+      # GN version: //webkit:resources
       'target_name': 'webkit_resources',
       'type': 'none',
       'variables': {
         'grit_out_dir': '<(SHARED_INTERMEDIATE_DIR)/webkit',
       },
       'actions': [
         {
           'action_name': 'webkit_resources',
           'variables': {
             'grit_grd_file': 'glue/resources/webkit_resources.grd',
           },
           'includes': [ '../build/grit_action.gypi' ],
         },
         {
           'action_name': 'blink_chromium_resources',
           'variables': {
             'grit_grd_file': '../third_party/WebKit/public/blink_resources.grd',
           },
           'includes': [ '../build/grit_action.gypi' ],
         },
       ],
       'includes': [ '../build/grit_target.gypi' ],
       'direct_dependent_settings': {
         'include_dirs': [ '<(grit_out_dir)' ],
       },
     },
     {
+      # GN version: //webkit:strings
       'target_name': 'webkit_strings',
       'type': 'none',
       'variables': {
         'grit_out_dir': '<(SHARED_INTERMEDIATE_DIR)/webkit',
       },
       'actions': [
         {
           'action_name': 'webkit_strings',
           'variables': {
             'grit_grd_file': 'glue/webkit_strings.grd',
           },
           'includes': [ '../build/grit_action.gypi' ],
         },
       ],
       'includes': [ '../build/grit_target.gypi' ],
     },
   ]
 }