Add first sketch of the webmodules code generator.

third_party/WebKit/Source/bindings/scripts/idl_compiler.py

 #!/usr/bin/python
 # Copyright (C) 2013 Google Inc. 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
@@ skipping 97 matching lines @@
         self.code_generator = code_generator_class(self.info_provider,
                                                    self.cache_directory,
                                                    self.output_directory)
 
     def compile_and_write(self, idl_filename):
         interface_name = idl_filename_to_interface_name(idl_filename)
         definitions = self.reader.read_idl_definitions(idl_filename)
         target_definitions = definitions[self.target_component]
         output_code_list = self.code_generator.generate_code(
             target_definitions, interface_name)
+
+        # Generator may choose to omit the file.
+        if output_code_list is None:
+            return
+
         for output_path, output_code in output_code_list:
             write_file(output_code, output_path)
 
     def compile_file(self, idl_filename):
         self.compile_and_write(idl_filename)
 
 
 def generate_bindings(code_generator_class, info_provider, options,
                       input_filenames):
     idl_compiler = IdlCompiler(
@@ skipping 63 matching lines @@
         generate_callback_function_impl(CodeGeneratorCallbackFunction,
                                         info_provider, options)
     else:
         # |input_filename| should be a path of an IDL file.
         generate_bindings(CodeGeneratorV8, info_provider, options,
                           [input_filename])
 
 
 if __name__ == '__main__':
     sys.exit(main())