Android: Fix one issue for instrumentation on "user" devices.

build/android/pylib/android_commands.py

Index: build/android/pylib/android_commands.py
diff --git a/build/android/pylib/android_commands.py b/build/android/pylib/android_commands.py
index 5e731173dccb9a2189aef1d7ea9db27363bf87de..de211d8112b7a7afdfe4853fddee0ac06feef3d6 100644
--- a/build/android/pylib/android_commands.py
+++ b/build/android/pylib/android_commands.py
@@ -219,7 +219,7 @@ class AndroidCommands(object):
       self._adb.SetTargetSerial(device)
     # So many users require root that we just always do it. This could
     # be made more fine grain if necessary.
-    self._adb.EnableAdbRoot()
+    self._root_enabled = self._adb.EnableAdbRoot()
     self._logcat = None
     self._original_governor = None
     self._pushed_files = []
@@ -229,6 +229,10 @@ class AndroidCommands(object):
     """Returns our AdbInterface to avoid us wrapping all its methods."""
     return self._adb
 
+  def IsRootEnabled(self):
+    """Returns whether or not _adb.EnabledAdbRoot() has succeeded."""
+    return self._root_enabled
+
   def GetDeviceYear(self):
     """Returns the year information of the date on device"""
     return self.RunShellCommand('date +%Y')[0]