Revert of perf: Disable battor.tough_video_cases on Mac as it is failing consistenly

tools/perf/benchmarks/battor.py

 # Copyright 2016 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 core import perf_benchmark
 from telemetry.timeline import chrome_trace_category_filter
 from telemetry.web_perf import timeline_based_measurement
 import page_sets
 from telemetry import benchmark
 
@@ skipping 29 matching lines @@
     galaxy_s5_type_name = 'SM-G900H'
     return possible_browser.platform.GetDeviceTypeName() == galaxy_s5_type_name
 
   @classmethod
   def ShouldTearDownStateAfterEachStoryRun(cls):
     return True
 
 
 # android: See battor.android.tough_video_cases below
 # win8: crbug.com/531618
-# mac: crbug.com/650411
 # crbug.com/565180: Only include cases that report time_to_play
 # Taken directly from media benchmark.
-@benchmark.Disabled('android', 'win8', 'mac')
+@benchmark.Disabled('android', 'win8')
 class BattOrToughVideoCases(_BattOrBenchmark):
   """Obtains media metrics for key user scenarios."""
   page_set = page_sets.ToughVideoCasesPageSet
 
   @classmethod
   def Name(cls):
     return 'battor.tough_video_cases'
 
 
 # TODO(rnephew): Add a version that scrolls.
@@ skipping 75 matching lines @@
 @benchmark.Enabled('mac')
 class BattOrSteadyStatePages(_BattOrBenchmark):
 
   def CreateStorySet(self, options):
     # We want it to wait for 30 seconds to be comparable to legacy power tests.
     return page_sets.IdleAfterLoadingStories(wait_in_seconds=30)
 
   @classmethod
   def Name(cls):
     return 'battor.steady_state'