Add wrapper method for enabling adb root.

build/android/pylib/android_commands.py

 # 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.
 
 """Provides an interface to communicate with the device via the adb command.
 
 Assumes adb binary is currently on system path.
 """
 
 import collections
@@ skipping 197 matching lines @@
 
   def Adb(self):
     """Returns our AdbInterface to avoid us wrapping all its methods."""
     return self._adb
 
   def IsRootEnabled(self):
     """Checks if root is enabled on the device."""
     root_test_output = self.RunShellCommand('ls /root') or ['']
     return not 'Permission denied' in root_test_output[0]
 
+  def EnableAdbRoot(self):
+    """Enables adb root on the device.
+
+      Returns:
+        True: if output from executing adb reboot was as expected.

[bulach, 2012/09/21 10:36:46]

nit: s/reboot/root/ :)
also, I think 221-223 needs to be unindented by 1 space, i.e., Returns is
aligned with the first quote """ from 219 (see 243-249 and other blocks below..)

[shashi, 2012/09/24 18:33:28]

Oops my bad, I have a CL to fix this.
On 2012/09/21 10:36:46, bulach wrote:

+        False: otherwise.
+    """
+    return_value = self._adb.EnableAdbRoot()
+    # EnableAdbRoot inserts a call for wait-for-device only when adb logcat
+    # output matches what is expected. Just to be safe add a call to
+    # wait-for-device.
+    self._adb.SendCommand('wait-for-device')
+    return return_value
+
   def GetDeviceYear(self):
     """Returns the year information of the date on device."""
     return self.RunShellCommand('date +%Y')[0]
 
   def GetExternalStorage(self):
     if not self._external_storage:
       self._external_storage = self.RunShellCommand('echo $EXTERNAL_STORAGE')[0]
       assert self._external_storage, 'Unable to find $EXTERNAL_STORAGE'
     return self._external_storage
 
@@ skipping 766 matching lines @@
     """
     assert '"' not in file_name, 'file_name cannot contain double quotes'
     status = self._adb.SendShellCommand(
         '\'test -e "%s"; echo $?\'' % (file_name))
     if 'test: not found' not in status:
       return int(status) == 0
 
     status = self._adb.SendShellCommand(
         '\'ls "%s" >/dev/null 2>&1; echo $?\'' % (file_name))
     return int(status) == 0