Revert of [Android][Telemetry] Add support for multiple power monitors

tools/telemetry/telemetry/internal/platform/power_monitor/sysfs_power_monitor.py

Index: tools/telemetry/telemetry/internal/platform/power_monitor/sysfs_power_monitor.py
diff --git a/tools/telemetry/telemetry/internal/platform/power_monitor/sysfs_power_monitor.py b/tools/telemetry/telemetry/internal/platform/power_monitor/sysfs_power_monitor.py
index 528e068a89af20c37f807b2330bd22b66a218466..9ebbe088f194141de688783fe21cf5e6ccbe4e3c 100644
--- a/tools/telemetry/telemetry/internal/platform/power_monitor/sysfs_power_monitor.py
+++ b/tools/telemetry/telemetry/internal/platform/power_monitor/sysfs_power_monitor.py
@@ -18,14 +18,11 @@
   """PowerMonitor that relies on sysfs to monitor CPU statistics on several
   different platforms.
   """
-  # TODO(rnephew): crbug.com/513453
-  # Convert all platforms to use standalone power monitors.
-  def __init__(self, linux_based_platform_backend, standalone=False):
+  def __init__(self, linux_based_platform_backend):
     """Constructor.
 
     Args:
         linux_based_platform_backend: A LinuxBasedPlatformBackend object.
-        standalone: If it is not wrapping another monitor, set to True.
 
     Attributes:
         _cpus: A list of the CPUs on the target device.
@@ -45,7 +42,6 @@
     self._initial_cstate = None
     self._initial_freq = None
     self._platform = linux_based_platform_backend
-    self._standalone = standalone
 
   @decorators.Cache
   def CanMonitorPower(self):
@@ -78,8 +74,6 @@
         for cpu in frequencies:
           out[cpu] = {'frequency_percent': frequencies[cpu]}
           out[cpu]['cstate_residency_percent'] = cstates[cpu]
-      if self._standalone:
-        return self.CombineResults(out, {})
       return out
     finally:
       self._initial_cstate = None