Revert of [Telemetry] Remove empty action_name_to_run for Startup, SessionRestore

tools/perf/measurements/startup.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.
 
 from metrics import startup_metric
 from telemetry.page import page_test
 
 
 class Startup(page_test.PageTest):
   """Performs a measurement of Chromium's startup performance.
 
   Uses cold start if cold==True, otherwise uses warm start. A cold start means
   none of the Chromium files are in the disk cache. A warm start assumes the OS
   has already cached much of Chromium's content. For warm tests, you should
   repeat the page set to ensure it's cached.
   """
 
-  def __init__(self, cold=False, action_name_to_run='RunPageInteractions'):
+  def __init__(self, cold=False, action_name_to_run=''):
     super(Startup, self).__init__(needs_browser_restart_after_each_page=True,
                                   action_name_to_run=action_name_to_run)
     self._cold = cold
 
   def CustomizeBrowserOptions(self, options):
     if self._cold:
       options.clear_sytem_cache_for_browser_and_profile_on_start = True
     else:
       self.discard_first_result = True
 
@@ skipping 17 matching lines @@
   has already cached much of Chromium's content. For warm tests, you should
   repeat the page set to ensure it's cached.
 
   The startup URL is taken from the page's startup_url. This
   allows the testing of multiple different URLs in a single benchmark.
   """
 
   def __init__(self, cold=False):
     super(StartWithUrl, self).__init__(cold=cold,
                                        action_name_to_run='RunPageInteractions')