[android] FlagChanger should only require root to set flags for Chrome.

build/android/tombstones.py

 #!/usr/bin/env python
 #
 # 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.
 #
 # Find the most recent tombstone file(s) on all connected devices
 # and prints their stacks.
 #
 # Assumes tombstone file was created with current symbols.
@@ skipping 52 matching lines @@
   """
   return adb.GetProtectedFileContents('/data/tombstones/' + tombstone_file)
 
 
 def _EraseTombstone(adb, tombstone_file):
   """Deletes a tombstone from the device.
 
   Args:
     tombstone_file: the tombstone to delete.
   """
-  return adb.RunShellCommand('su -c rm /data/tombstones/' + tombstone_file)
+  return adb.RunShellCommandWithSU('rm /data/tombstones/' + tombstone_file)
 
 
 def _ResolveSymbols(tombstone_data, include_stack):
   """Run the stack tool for given tombstone input.
 
   Args:
     tombstone_data: a list of strings of tombstone data.
     include_stack: boolean whether to include stack data in output.
 
   Yields:
@@ skipping 102 matching lines @@
 
   tombstones = []
   for device in devices:
     adb = android_commands.AndroidCommands(device)
     tombstones += _GetTombstonesForDevice(adb, options)
 
   _ResolveTombstones(options.jobs, tombstones)
 
 if __name__ == '__main__':
   sys.exit(main())