[Telemetry] Explicitly define Name() method for all perf benchmarks

tools/perf/benchmarks/power.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 from measurements import power
 import page_sets
 from telemetry import benchmark
 
 
 @benchmark.Enabled('android')
 class PowerAndroidAcceptance(benchmark.Benchmark):
-
   """Android power acceptance test."""
-
   test = power.Power
   page_set = page_sets.AndroidAcceptancePageSet
+  @classmethod
+  def Name(cls):
+    return 'power.android_acceptance'
+
 
 
 @benchmark.Enabled('android')
 class PowerTypical10Mobile(benchmark.Benchmark):
-
   """Android typical 10 mobile power test."""
-
   test = power.Power
   page_set = page_sets.Typical10MobilePageSet
+  @classmethod
+  def Name(cls):
+    return 'power.typical_10_mobile'
+
+