Save the logcat file in isolated directory.

tools/mb/mb.py

 #!/usr/bin/env python
 # Copyright 2015 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.
 
 """MB - the Meta-Build wrapper around GYP and GN
 
 MB is a wrapper script for GYP and GN that can be used to generate build files
 for sets of canned configurations and analyze them.
 """
@@ skipping 1073 matching lines @@
 
     if test_type == 'nontest':
       self.WriteFailureAndRaise('We should not be isolating %s.' % target,
                                 output_path=None)
 
     if android and test_type != "script":
       cmdline = [
           '../../build/android/test_wrapper/logdog_wrapper.py',
           '--target', target,
           '--target-devices-file', '${SWARMING_BOT_FILE}',
-          '--logdog-bin-cmd', '../../bin/logdog_butler']
+          '--logdog-bin-cmd', '../../bin/logdog_butler',
+          '--logcat-output-file', '${ISOLATED_OUTDIR}/logcats']
     elif use_xvfb and test_type == 'windowed_test_launcher':
       extra_files = [
           '../../testing/test_env.py',
           '../../testing/xvfb.py',
       ]
       cmdline = [
         '../../testing/xvfb.py',
         './' + str(executable) + executable_suffix,
         '--brave-new-test-launcher',
         '--test-launcher-bot-mode',
@@ skipping 453 matching lines @@
   # Then check to see if the arg contains any metacharacters other than
   # double quotes; if it does, quote everything (including the double
   # quotes) for safety.
   if any(a in UNSAFE_FOR_CMD for a in arg):
     arg = ''.join('^' + a if a in ALL_META_CHARS else a for a in arg)
   return arg
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))