[Telemetry] Remove empty action_name_to_run for Startup, SessionRestore

tools/perf/measurements/session_restore.py

 # Copyright 2013 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 collections
 
 from measurements import startup
 from metrics import cpu
 from metrics import startup_metric
 from telemetry.core import util
 from telemetry.value import histogram_util
 
 
 class SessionRestore(startup.Startup):
   """Performs a measurement of Chromium's Session restore performance.
 
   This test is meant to be run against a generated profile.
   This test inherits support for the 'cold' option -
   see startup.py for details.
   """
 
-  def __init__(self, cold=False, action_name_to_run = ''):
+  def __init__(self, cold=False, action_name_to_run='RunPageInteractions'):
     super(SessionRestore, self).__init__(cold=cold,
                                          action_name_to_run=action_name_to_run)
     self.close_tabs_before_run = False
     self._cpu_metric = None
 
   def CustomizeBrowserOptions(self, options):
     super(SessionRestore, self).CustomizeBrowserOptions(options)
     histogram_util.CustomizeBrowserOptions(options)
     options.AppendExtraBrowserArgs([
         '--restore-last-session'
@@ skipping 38 matching lines @@
   def ValidateAndMeasurePage(self, page, tab, results):
     tab.WaitForDocumentReadyStateToBeComplete()
 
     # Record CPU usage from browser start to when the foreground page is loaded.
     self._cpu_metric.Stop(None, None)
     self._cpu_metric.AddResults(tab, results, 'cpu_utilization')
 
     startup_metric.StartupMetric().AddResults(tab, results)
 
     # TODO(jeremy): Measure time to load - first, last and frontmost tab here.