Move InitializeICU() to the V8 API and use it.

src/d8.gyp

 # Copyright 2012 the V8 project authors. 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
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 62 matching lines @@
               'sources': [ 'd8-windows.cc', ]
             }],
           ],
         }],
         ['v8_enable_vtunejit==1', {
           'dependencies': [
             '../src/third_party/vtune/v8vtune.gyp:v8_vtune',
           ],
         }],
         ['v8_enable_i18n_support==1', {
-          'sources': [
-            'icu_util.cc',
-            'icu_util.h',
-          ],
           'dependencies': [
             '<(DEPTH)/third_party/icu/icu.gyp:*',
           ],
         }],
       ],
     },
     {
       'target_name': 'd8_js2c',
       'type': 'none',
       'variables': {
@@ skipping 25 matching lines @@
             '<@(_outputs)',
             'D8',
             'off',  # compress startup data
             '<@(js_files)'
           ],
         },
       ],
     }
   ],
 }