[BotHealth] Disable PCv2 on reference using ShouldDisable

tools/perf/benchmarks/page_cycler_v2.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.
 
 """The page cycler v2.
 
 For details, see design doc:
 https://docs.google.com/document/d/1EZQX-x3eEphXupiX-Hq7T4Afju5_sIdxPWYetj7ynd0
 """
 
 from core import perf_benchmark
 import page_sets
 
 from telemetry import benchmark
 from telemetry.page import cache_temperature
 from telemetry.timeline import chrome_trace_category_filter
 from telemetry.web_perf import timeline_based_measurement
 
 
-# crbug.com/619254
-@benchmark.Disabled('reference')
 class _PageCyclerV2(perf_benchmark.PerfBenchmark):
   options = {'pageset_repeat': 2}
 
   def CreateTimelineBasedMeasurementOptions(self):
     cat_filter = chrome_trace_category_filter.ChromeTraceCategoryFilter(
         filter_string='blink.console,navigation,blink.user_timing,loading')
 
     # Below categories are needed for first-meaningful-paint computation.
     cat_filter.AddDisabledByDefault('disabled-by-default-blink.debug.layout')
     cat_filter.AddIncludedCategory('devtools.timeline')
 
     tbm_options = timeline_based_measurement.Options(
         overhead_level=cat_filter)
     tbm_options.SetTimelineBasedMetrics(['loadingMetric'])
     return tbm_options
 
   @classmethod
   def ShouldDisable(cls, possible_browser):
+    # crbug.com/619254
+    if possible_browser.browser_type == 'reference':
+      return True
+
     # crbug.com/616781
     if (cls.IsSvelte(possible_browser) or
         possible_browser.platform.GetDeviceTypeName() == 'Nexus 5X' or
         possible_browser.platform.GetDeviceTypeName() == 'AOSP on BullHead'):
       return True
     return False
 
 
 class PageCyclerV2Typical25(_PageCyclerV2):
   """Page load time benchmark for a 25 typical web pages.
@@ skipping 145 matching lines @@
   set, without running in out-of-process iframes mode.. """
   page_set = page_sets.OopifBasicPageSet
 
   @classmethod
   def Name(cls):
     return 'page_cycler_v2.basic_oopif'
 
   def CreateStorySet(self, options):
     return page_sets.OopifBasicPageSet(cache_temperatures=[
           cache_temperature.PCV1_COLD, cache_temperature.PCV1_WARM])