Android: Auto-detect output directory in generate_gradle.py

build/android/gradle/generate_gradle.py

 #!/usr/bin/env python
 # Copyright 2016 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.
 
 """Generates an Android Studio project from a GN target."""
 
 import argparse
 import codecs
 import logging
@@ skipping 470 matching lines @@
       entry.android_test_entry = android_test_entries[target_name]
       del android_test_entries[target_name]
   # Add unmatched test entries as individual targets.
   combined_entries.extend(android_test_entries.values())
   return combined_entries
 
 
 def main():
   parser = argparse.ArgumentParser()
   parser.add_argument('--output-directory',
-                      default='out/Debug',
                       help='Path to the root build directory.')
   parser.add_argument('-v',
                       '--verbose',
                       dest='verbose_count',
                       default=0,
                       action='count',
                       help='Verbose level')
   parser.add_argument('--target',
                       dest='targets',
                       action='append',
@@ skipping 89 matching lines @@
     _ExtractSrcjars(generator.project_dir, srcjar_tuples)
 
   logging.warning('Project created! (%d subprojects)', len(project_entries))
   logging.warning('Generated projects work best with Android Studio 2.2')
   logging.warning('For more tips: https://chromium.googlesource.com/chromium'
                   '/src.git/+/master/docs/android_studio.md')
 
 
 if __name__ == '__main__':
   main()