Update from https://crrev.com/305340

build/android/pylib/perf/perf_control_unittest.py

 # Copyright 2014 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.
 # pylint: disable=W0212
 
 import os
 import sys
 import unittest
 
 sys.path.append(os.path.join(os.path.dirname(__file__), os.pardir, os.pardir))
 
 from pylib import android_commands
 from pylib.device import device_utils
 from pylib.perf import perf_control
 
 class TestPerfControl(unittest.TestCase):
   def setUp(self):
     if not os.getenv('BUILDTYPE'):
       os.environ['BUILDTYPE'] = 'Debug'
 
     devices = android_commands.GetAttachedDevices()
     self.assertGreater(len(devices), 0, 'No device attached!')
     self._device = device_utils.DeviceUtils(
         android_commands.AndroidCommands(device=devices[0]))
 
   def testHighPerfMode(self):
     perf = perf_control.PerfControl(self._device)
     try:
       perf.SetPerfProfilingMode()
-      for cpu in range(perf._num_cpu_cores):
-        path = perf_control.PerfControl._CPU_ONLINE_FMT % cpu
-        self.assertEquals('1',
-                          self._device.ReadFile(path)[0])
-        path = perf_control.PerfControl._SCALING_GOVERNOR_FMT % cpu
-        self.assertEquals('performance',
-                          self._device.ReadFile(path)[0])
+      cpu_info = perf.GetCpuInfo()
+      self.assertEquals(len(perf._cpu_files), len(cpu_info))
+      for _, online, governor in cpu_info:
+        self.assertTrue(online)
+        self.assertEquals('performance', governor)
     finally:
       perf.SetDefaultPerfMode()
 
 if __name__ == '__main__':
   unittest.main()