Improve CLI interface of C++ enums to Java generator

build/android/java_cpp_enum.gypi

 # 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.
 
 # This file is meant to be included into a target to provide an action
 # to generate Java source files from a C++ header file containing annotated
 # enum definitions using a Python script.
 #
 # To use this, create a gyp target with the following form:
 #  {
 #    'target_name': 'bitmap_format_java',
 #    'type': 'none',
 #    'variables': {
 #      'source_file': 'ui/android/bitmap_format.h',
 #    },
 #    'includes': [ '../build/android/java_cpp_enum.gypi' ],
 #  },
 #
 # Then have the gyp target which compiles the java code depend on the newly
 # created target.
 
 {
   'variables': {
     # Location where all generated Java sources will be placed.
     'output_dir': '<(SHARED_INTERMEDIATE_DIR)/enums/<(_target_name)',
     'generator_path': '<(DEPTH)/build/android/gyp/java_cpp_enum.py',
-    'generator_args': '--output_dir=<(output_dir) <(source_file)',
+    'generator_args': '<(output_dir) <(source_file)',
   },
   'direct_dependent_settings': {
     'variables': {
       # Ensure that the output directory is used in the class path
       # when building targets that depend on this one.
       'generated_src_dirs': [
         '<(output_dir)/',
       ],
     },
   },
@@ skipping 12 matching lines @@
         '<!@pymod_do_main(java_cpp_enum --print_output_only '
             '<@(generator_args))',
       ],
       'action': [
         'python', '<(generator_path)', '<@(generator_args)'
       ],
       'message': 'Generating Java from cpp header <(source_file)',
     },
   ],
 }