[tracing] Add support for TracedValue JSON serializer.

test/cctest/cctest.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 169 matching lines @@
       'test-representation.cc',
       'test-sampler-api.cc',
       'test-serialize.cc',
       'test-simd.cc',
       'test-strings.cc',
       'test-symbols.cc',
       'test-strtod.cc',
       'test-thread-termination.cc',
       'test-threads.cc',
       'test-trace-event.cc',
+      'test-traced-value.cc',
       'test-transitions.cc',
       'test-typedarrays.cc',
       'test-ast-types.cc',
       'test-types.cc',
       'test-unbound-queue.cc',
       'test-unboxed-doubles.cc',
       'test-unique.cc',
       'test-unscopables-hidden-prototype.cc',
       'test-usecounters.cc',
       'test-utils.cc',
@@ skipping 318 matching lines @@
             '../../gypfiles/isolate.gypi',
           ],
           'sources': [
             'cctest.isolate',
           ],
         },
       ],
     }],
   ],
 }