Add jbroman to WATCHLISTS for src/value-serializer.*.

WATCHLISTS

 # Copyright 2013 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 52 matching lines @@
     'gypfiles': {
       'filepath': 'gypfiles/',
     },
     'inspector': {
       'filepath': 'inspector',
     },
     'wasm': {
       'filepath': 'src/wasm/' \
                   '|src/compiler/wasm',
     },
+    'value_serializer': {
+      'filepath': 'src/value-serializer',
+    }
   },
 
   'WATCHLISTS': {
     'snapshot': [
       'yangguo@chromium.org',
     ],
     'debugger': [
       'yangguo@chromium.org',
     ],
     'interpreter': [
@@ skipping 19 matching lines @@
     ],
     'gypfiles': [
       'machenbach@chromium.org',
     ],
     'inspector': [
       'devtools-reviews@chromium.org',
     ],
     'wasm': [
       'wasm-v8@google.com',
     ],
+    'value_serializer': [
+      'jbroman+watch@chromium.org',
+    ],
   },
 }