[Telemetry] Measure power in tab_switching measurement

tools/telemetry/telemetry/core/platform/platform_backend_unittest.py

Index: tools/telemetry/telemetry/core/platform/platform_backend_unittest.py
diff --git a/tools/telemetry/telemetry/core/platform/platform_backend_unittest.py b/tools/telemetry/telemetry/core/platform/platform_backend_unittest.py
index 4909349d7fd4b5101910981155e141815063aa9a..2e568bec11427520ffd60dd1bde5d2d74a1f40a1 100644
--- a/tools/telemetry/telemetry/core/platform/platform_backend_unittest.py
+++ b/tools/telemetry/telemetry/core/platform/platform_backend_unittest.py
@@ -9,13 +9,14 @@ from telemetry.core.platform import factory
 
 
 class PlatformBackendTest(unittest.TestCase):
-  def testPowerMonitoringSync(self):
+  def testPowerMonitoringAsync(self):
     # Tests that the act of monitoring power doesn't blow up.
     backend = factory.GetPlatformBackendForCurrentOS()
-    if not backend.CanMonitorPowerSync():
+    if not backend.CanMonitorPowerAsync():
       logging.warning('Test not supported on this platform.')
       return
 
-    output = backend.MonitorPowerSync(1)
+    backend.StartMonitoringPowerAsync()
+    output = backend.StopMonitoringPowerAsync()
     self.assertTrue(output.has_key('power_samples_mw'))
     self.assertTrue(output.has_key('identifier'))