Revert of Revert of DevTools: Introduce module initializers

Source/devtools/scripts/concatenate_module_descriptors.py

 #!/usr/bin/env python
 #
 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Inlines all module.json files into modules.js."""
 
 from os import path
 import errno
 import shutil
 import sys
+try:
+    import simplejson as json
+except ImportError:
+    import json
 
 
 def read_file(filename):
     with open(filename, 'rt') as file:
         return file.read()
 
 
 def build_modules(module_jsons):
     result = []
     for json_filename in module_jsons:
         if not path.exists(json_filename):
             continue
         module_name = path.basename(path.dirname(json_filename))
-        json = read_file(json_filename).replace('{', '{"name":"%s",' % module_name, 1)
-        result.append(json)
-    return ','.join(result)
+
+        # pylint: disable=E1103
+        module_json = json.loads(read_file(json_filename))
+        module_json['name'] = module_name
+
+        # Clear scripts, as they are not used at runtime
+        # (only the fact of their presence is important).
+        if module_json.get('scripts'):
+            module_json['scripts'] = []
+        result.append(module_json)
+    return json.dumps(result)
 
 
 def main(argv):
     input_filename = argv[1]
     output_filename = argv[2]
     module_jsons = argv[3:]
 
     with open(output_filename, 'w') as output_file:
-        output_file.write('var allDescriptors=[%s];' % build_modules(module_jsons))
+        output_file.write('var allDescriptors=%s;' % build_modules(module_jsons))
 
 
 if __name__ == '__main__':
     sys.exit(main(sys.argv))