[Android] Reland cleanup of old_interface in build/android/pylib.

build/android/pylib/perf/perf_control.py

Index: build/android/pylib/perf/perf_control.py
diff --git a/build/android/pylib/perf/perf_control.py b/build/android/pylib/perf/perf_control.py
index 97fa4a7ee16c55709aa1658fdee466bfbe942a95..b6a0989eb9f052c7e54459f7b0e1e725d54b90a3 100644
--- a/build/android/pylib/perf/perf_control.py
+++ b/build/android/pylib/perf/perf_control.py
@@ -28,7 +28,7 @@ class PerfControl(object):
 
   def SetHighPerfMode(self):
     """Sets the highest stable performance mode for the device."""
-    if not self._device.old_interface.IsRootEnabled():
+    if not self._device.HasRoot():
       message = 'Need root for performance mode. Results may be NOISY!!'
       logging.warning(message)
       # Add an additional warning at exit, such that it's clear that any results
@@ -58,13 +58,13 @@ class PerfControl(object):
     self._ForceAllCpusOnline(True)
     self._SetScalingGovernorInternal('performance')
     if not self._AllCpusAreOnline():
-      if not self._device.old_interface.IsRootEnabled():
+      if not self._device.HasRoot():
         raise RuntimeError('Need root to force CPUs online.')
       raise RuntimeError('Failed to force CPUs online.')
 
   def SetDefaultPerfMode(self):
     """Sets the performance mode for the device to its default mode."""
-    if not self._device.old_interface.IsRootEnabled():
+    if not self._device.HasRoot():
       return
     product_model = self._device.product_model
     if 'Nexus 5' == product_model: