Add json-stringifier.h to v8.gyp.

tools/gyp/v8.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 335 matching lines @@
             '../../src/incremental-marking.h',
             '../../src/inspector.cc',
             '../../src/inspector.h',
             '../../src/interface.cc',
             '../../src/interface.h',
             '../../src/interpreter-irregexp.cc',
             '../../src/interpreter-irregexp.h',
             '../../src/isolate.cc',
             '../../src/isolate.h',
             '../../src/json-parser.h',
+            '../../src/json-stringifier.h',
             '../../src/jsregexp.cc',
             '../../src/jsregexp.h',
             '../../src/lazy-instance.h',
             '../../src/list-inl.h',
             '../../src/list.h',
             '../../src/lithium-allocator-inl.h',
             '../../src/lithium-allocator.cc',
             '../../src/lithium-allocator.h',
             '../../src/lithium.cc',
             '../../src/lithium.h',
@@ skipping 631 matching lines @@
             }],
           ],
           'dependencies': [
             'v8'
           ],
         },
       ],
     }],
   ],
 }