[Android] Adding extension related file to Android isolate blacklist.

testing/generate_isolate.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.
 
 """Creates an .isolate given a list of files.
 
 """
 
 import argparse
 import os
 import pprint
 import re
 import sys
 
 
 _UNIVERSAL_BLACKLIST = (
     r'.*OWNERS',  # Should never be included.
 )
 
 _ANDROID_BLACKLIST = (
     r'.*\.crx',  # Chrome extension zip files.
+    r'.*external_extensions\.json',  # Chrome external extensions config file.
     r'.*\.so',  # Libraries packed into .apk.
     r'.*\.mojom\.js',  # Some test_support targets include python deps.
     r'.*Mojo.*manifest\.json',  # Some source_set()s pull these in.
     r'.*jni_generator_tests',  # Exists just to test the compile, not to be run.
 )
 
 _DEVICE_BLACKLIST = (
     r'.*\.py',  # Some test_support targets include python deps.
 )
 
@@ skipping 73 matching lines @@
   if options.out_file:
     with open(options.out_file, 'w') as f:
       f.write(isolate_data + '\n')
   else:
     print isolate_data
 
 
 if __name__ == '__main__':
   sys.exit(main())