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

tools/perf/benchmarks/scheduler.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 telemetry import benchmark
 from measurements import smoothness
 import page_sets
 
 
 class SchedulerToughSchedulingCases(benchmark.Benchmark):
   """Measures rendering statistics while interacting with pages that have
   challenging scheduling properties.
 
   https://docs.google.com/a/chromium.org/document/d/
       17yhE5Po9By0sCdM1yZT3LiUECaUr_94rQt9j-4tOQIM/view"""
   test = smoothness.Smoothness
   page_set = page_sets.ToughSchedulingCasesPageSet
+  @classmethod
+  def Name(cls):
+    return 'scheduler.tough_scheduling_cases'
+