[json] move json parser and stringifier into own compilation units.

src/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 905 matching lines @@
         'interpreter/interpreter.h',
         'interpreter/interpreter-assembler.cc',
         'interpreter/interpreter-assembler.h',
         'interpreter/interpreter-intrinsics.cc',
         'interpreter/interpreter-intrinsics.h',
         'interpreter/source-position-table.cc',
         'interpreter/source-position-table.h',
         'isolate-inl.h',
         'isolate.cc',
         'isolate.h',
+        'json-parser.cc',
         'json-parser.h',
+        'json-stringifier.cc',
         'json-stringifier.h',
         'keys.h',
         'keys.cc',
         'layout-descriptor-inl.h',
         'layout-descriptor.cc',
         'layout-descriptor.h',
         'list-inl.h',
         'list.h',
         'locked-queue-inl.h',
         'locked-queue.h',
@@ skipping 1305 matching lines @@
         }],
         ['want_separate_host_toolset==1', {
           'toolsets': ['host'],
         }, {
           'toolsets': ['target'],
         }],
       ],
     },
   ],
 }