[Android] Clear adb logcat during adb_logcat_monitor startup.

build/android/adb_logcat_monitor.py

 #!/usr/bin/env python
 #
 # Copyright (c) 2012 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.
 
 """Saves logcats from all connected devices.
 
 Usage: adb_logcat_monitor.py <base_dir> [<adb_binary_path>]
 
@@ skipping 108 matching lines @@
 
   logging.info('Started with pid %d', os.getpid())
   pid_file_path = os.path.join(base_dir, 'LOGCAT_MONITOR_PID')
 
   try:
     with open(pid_file_path, 'w') as f:
       f.write(str(os.getpid()))
     while True:
       for device_id in GetAttachedDevices(adb_cmd):
         if not device_id in devices:
+          subprocess.call([adb_cmd, '-s', device_id, 'logcat', '-c'])

[Isaac (away), 2013/06/19 00:10:33]

This should only be done during initialization, not during loop.

[frankf, 2013/06/19 00:18:54]

No, this is the first time you're seeing this device. Look at line 128.

On 2013/06/19 00:10:33, Isaac wrote:

           devices[device_id] = (None, 0)
 
       for device in devices:
         # This will spawn logcat watchers for any device ever detected
         StartLogcatIfNecessary(device, adb_cmd, base_dir)
 
       time.sleep(5)
   except SigtermError:
     logging.info('Received SIGTERM, shutting down')
   except:
     logging.exception('Unexpected exception in main.')
   finally:
     for process, _ in devices.itervalues():
       if process:
         try:
           process.terminate()
         except OSError:
           pass
     os.remove(pid_file_path)
 
 
 if __name__ == '__main__':
   if 2 <= len(sys.argv) <= 3:
     print 'adb_logcat_monitor: Initializing'
     sys.exit(main(*sys.argv[1:3]))
 
   print 'Usage: %s <base_dir> [<adb_binary_path>]' % sys.argv[0]