Adding dumpsys based power monitor for android.

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..d4267f7fa6c5ea30d39cf72b962c18bb3da4f1e0 100644
--- a/tools/telemetry/telemetry/core/platform/platform_backend_unittest.py
+++ b/tools/telemetry/telemetry/core/platform/platform_backend_unittest.py
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import logging
+import time
 import unittest
 
 from telemetry.core.platform import factory
@@ -12,10 +13,20 @@ class PlatformBackendTest(unittest.TestCase):
   def testPowerMonitoringSync(self):
     # Tests that the act of monitoring power doesn't blow up.
     backend = factory.GetPlatformBackendForCurrentOS()
-    if not backend.CanMonitorPowerSync():
+    if not backend.CanMonitorPower():
       logging.warning('Test not supported on this platform.')
       return
 
-    output = backend.MonitorPowerSync(1)
+    browser_mock = lambda: None
+    # Android needs to access the package of the monitored app.
+    if backend.GetOSName() == 'android':
+      # pylint: disable=W0212
+      browser_mock._browser_backend = lambda: None
+      # Monitor the launcher, which is always present.
+      browser_mock._browser_backend.package = 'com.android.launcher'
+
+    backend.StartMonitoringPower(browser_mock)
+    time.sleep(0.001)
+    output = backend.StopMonitoringPower()
     self.assertTrue(output.has_key('power_samples_mw'))
     self.assertTrue(output.has_key('identifier'))