telemetry: Allow page tests to be configured via constructor

tools/telemetry/telemetry/web_perf/timeline_based_measurement.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.
 
 import logging
 import os
 from collections import defaultdict
 
 from telemetry.core import util
 from telemetry.core.platform import tracing_category_filter
@@ skipping 122 matching lines @@
   information.
 
   For information on how to mark up a page to work with
   TimelineBasedMeasurement, refer to the
   perf.metrics.timeline_interaction_record module.
 
   """
   def __init__(self):
     super(TimelineBasedMeasurement, self).__init__('RunPageInteractions')
 
-  @classmethod
-  def AddCommandLineArgs(cls, parser):
+  def AddCommandLineArgs(self, parser):
     parser.add_option(
         '--overhead-level', dest='overhead_level', type='choice',
         choices=ALL_OVERHEAD_LEVELS,
         default=NO_OVERHEAD_LEVEL,
         help='How much overhead to incur during the measurement.')
     parser.add_option(
         '--trace-dir', dest='trace_dir', type='string', default=None,
         help=('Where to save the trace after the run. If this flag '
               'is not set, the trace will not be saved.'))
 
@@ skipping 38 matching lines @@
 
     model = model_module.TimelineModel(trace_result)
     renderer_thread = model.GetRendererThreadFromTabId(tab.id)
     meta_metrics = _TimelineBasedMetrics(
         model, renderer_thread, _GetMetricFromMetricType)
     meta_metrics.AddResults(results)
 
   def CleanUpAfterPage(self, page, tab):
     if tab.browser.platform.tracing_controller.is_tracing_running:
       tab.browser.platform.tracing_controller.Stop()