[Telemetry] Disable webrtc.multiple_peerconnections story.

tools/perf/benchmarks/webrtc.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 core import perf_benchmark
 
 import page_sets
 from telemetry import benchmark
 from telemetry.timeline import chrome_trace_category_filter
 from telemetry.web_perf import timeline_based_measurement
 
 
 @benchmark.Owner(emails=['qiangchen@chromium.org', # For smoothness metrics
                          'ehmaldonado@chromium.org',
                          'phoglund@chromium.org'])
 class WebrtcPerfBenchmark(perf_benchmark.PerfBenchmark):
   """Base class for WebRTC metrics for real-time communications tests."""
   page_set = page_sets.WebrtcPageSet
 
   @classmethod
   def Name(cls):
     return 'webrtc'
 
-  def GetExpectations(self):
-    return page_sets.WebrtcExpectations()
-
   def CreateTimelineBasedMeasurementOptions(self):
     categories = [
         # Disable all categories by default.
         '-*',
         'toplevel',
         # WebRTC
         'webrtc',
     ]
 
     category_filter = chrome_trace_category_filter.ChromeTraceCategoryFilter(
         filter_string=','.join(categories))
     options = timeline_based_measurement.Options(category_filter)
     options.SetTimelineBasedMetrics([
         'cpuTimeMetric',
         'webrtcRenderingMetric',
     ])
     return options
 
   def SetExtraBrowserOptions(self, options):
     options.AppendExtraBrowserArgs('--use-fake-device-for-media-stream')
     options.AppendExtraBrowserArgs('--use-fake-ui-for-media-stream')