[Android] Support idle wakeup measurement with /proc/timer_stats

tools/telemetry/telemetry/internal/platform/linux_based_platform_backend.py

Index: tools/telemetry/telemetry/internal/platform/linux_based_platform_backend.py
diff --git a/tools/telemetry/telemetry/internal/platform/linux_based_platform_backend.py b/tools/telemetry/telemetry/internal/platform/linux_based_platform_backend.py
index f22b7bae3e21d4bd2ad183dc222c529083a20046..9ff75197d3a1f47c969f045c2d3238a9db06933f 100644
--- a/tools/telemetry/telemetry/internal/platform/linux_based_platform_backend.py
+++ b/tools/telemetry/telemetry/internal/platform/linux_based_platform_backend.py
@@ -110,6 +110,12 @@ class LinuxBasedPlatformBackend(platform_backend.PlatformBackend):
     """
     raise NotImplementedError()
 
+  def StartMeasuringIdleWakeUps(self):
+    self._EnableTimerStatsCollection(True)
+
+  def StopMeasuringIdleWakeUps(self):
+    self._EnableTimerStatsCollection(False)
+
   @staticmethod
   def ParseCStateSample(sample):
     """Parse a single c-state residency sample.
@@ -130,6 +136,11 @@ class LinuxBasedPlatformBackend(platform_backend.PlatformBackend):
     assert pid, 'pid is required'
     return bool(self.GetPsOutput(['pid'], pid) == str(pid))
 
+  def _EnableTimerStatsCollection(self, enable):
+    """Writes to /proc/timer_stats to start/stop measuring process wakeups."""
+    # TODO(thestig) Implement on Linux and CrOS.
+    raise NotImplementedError()
+
   def _GetProcFileForPid(self, pid, filename):
     try:
       return self.GetFileContents('/proc/%s/%s' % (pid, filename))