Telemetry: Implement idle wakeups counting on Android.

tools/telemetry/telemetry/core/platform/android_platform_backend.py

Index: tools/telemetry/telemetry/core/platform/android_platform_backend.py
diff --git a/tools/telemetry/telemetry/core/platform/android_platform_backend.py b/tools/telemetry/telemetry/core/platform/android_platform_backend.py
index 27ebfc99b4cc15bb33c8aa7b8d3ae31d919a0841..fe3f84e3a9cc6bca7c323a7b1113a867f1b47a1a 100644
--- a/tools/telemetry/telemetry/core/platform/android_platform_backend.py
+++ b/tools/telemetry/telemetry/core/platform/android_platform_backend.py
@@ -298,6 +298,9 @@ class AndroidPlatformBackend(
   def CanMonitorPower(self):
     return self._power_monitor.CanMonitorPower()
 
+  def CanMeasureIdleWakeUps(self):
+    return True
+
   def StartMonitoringPower(self, browser):
     self._power_monitor.StartMonitoringPower(browser)
 
@@ -478,6 +481,12 @@ class AndroidPlatformBackend(
     """
     return '/data/data/%s/' % package
 
+  def _RunTimerStatsUtility(self, start):

[jeremy, 2014/11/05 07:28:11]

_EnableTimerStatsCollection ?
s/start/enable/

[Lei Zhang, 2014/11/06 04:52:49]

Done.

+    """Writes to /proc/timer_stats to start/stop measuring process wakeups."""
+    parameter = 1 if start else 0
+    cmd = 'echo %d > /proc/timer_stats' % parameter
+    self._device.RunShellCommand(cmd, as_root=True)
+
   def SetDebugApp(self, package):
     """Set application to debugging.