Make .pyc cleaning optional in clean_local_files.

scripts/slave/recipe_modules/webrtc/api.py

 # Copyright 2013 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.
 
 from recipe_engine.types import freeze
 from recipe_engine import recipe_api
 from . import builders
 from . import steps
 
 
@@ skipping 344 matching lines @@
        extra_url_components=self.mastername)
     self.m.archive.download_and_unzip_build(
         'extract build',
         self.m.chromium.c.build_config_fs,
         download_url,
         build_revision=self.revision)
 
   def cleanup(self):
     self.clean_test_output()
     if self.m.chromium.c.TARGET_PLATFORM == 'android':
-      self.m.chromium_android.clean_local_files()
+      self.m.chromium_android.clean_local_files(clean_pyc_files=False)
     else:
       self.m.chromium.cleanup_temp()
     if self.c.use_isolate:
       self.m.isolate.clean_isolated_files(self.m.chromium.output_dir)
 
   def clean_test_output(self):
     """Remove all test output in out/, since we have tests leaking files."""
     out_dir = self.m.path['checkout'].join('out')
     self.m.python('clean test output files',
                   script=self.resource('cleanup_files.py'),
                   args=[out_dir],
                   infra_step=True)
 
   def virtual_webcam_check(self):
     self.m.python('webcam_check', self.resource('ensure_webcam_is_running.py'))