Remove defunct reference to json.dart in copy_dart.py.

tools/copy_dart.py

 #!/usr/bin/env python
 # Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 """Used to merge and copy dart source files for deployment to AppEngine"""
 
 import fileinput
 import sys
 import shutil
 import os
@@ skipping 88 matching lines @@
       lib = worklist.pop()
       if lib in seen:
         continue
 
       seen.add(lib)
 
       if (dirname(dirname(lib)).endswith('dom/generated/src')
           or dirname(lib).endswith('dom/src')):
         continue
 
-      if lib.endswith('json/json.dart'):
-        # TODO(jmesserly): Dartium interprets "json.dart" as "dart_json.dart",
-        # so we need that add dart_json.dart here. This is hacky.
-        lib = lib.replace('json.dart', 'dart_json.dart')
-
       library = parseLibrary(lib)
 
       # Ensure output directory exists
       outpath = join(outdir, lib[1:] if isabs(lib) else lib)
       dstpath = dirname(outpath)
       if not exists(dstpath):
         os.makedirs(dstpath)
 
 
       # Create file containing all imports, and inlining all sources
@@ skipping 12 matching lines @@
       for suffix in library.imports:
         m = re.match(r'[\'"]([^\'"]+)[\'"](\s+as\s+\w+)?.*$', suffix)
         uri = m.group(1)
         if not uri.startswith('dart:'):
           worklist.append(normjoin(dirname(lib), uri));
 
   return 0
 
 if __name__ == '__main__':
   sys.exit(main(*sys.argv[1:]))