[system_health] Fix the lack of memory dump triggers on some user stories

tools/perf/page_sets/system_health/media_stories.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.
 
 from page_sets.system_health import platforms
 from page_sets.system_health import system_health_story
 
 from page_sets.login_helpers import google_login
 from page_sets.login_helpers import pandora_login
 
 
 class _MediaStory(system_health_story.SystemHealthStory):
   """Abstract base class for media System Health user stories."""
 
   ABSTRACT_STORY = True
   SUPPORTED_PLATFORMS = platforms.DESKTOP_ONLY
   PLAY_DURATION = 20
   PLAY_SELECTOR = NotImplemented
   STOP_SELECTOR = NotImplemented
   TIME_SELECTOR = NotImplemented
 
-  def RunPageInteractions(self, action_runner):
+  def _DidLoadDocument(self, action_runner):
     self._NavigateToMedia(action_runner)
     # Play Media.
     if self.PLAY_SELECTOR:
       self._WaitForAndClickElementBySelector(action_runner, self.PLAY_SELECTOR)
     self._WaitForPlayTime(action_runner)
     # Stop media.
     self._WaitForAndClickElementBySelector(action_runner, self.STOP_SELECTOR)
 
   def _NavigateToMedia(self, action_runner):
     raise NotImplementedError
@@ skipping 71 matching lines @@
   PLAY_SELECTOR = None
   STOP_SELECTOR = '.pauseButton'
   TIME_SELECTOR = '.elapsedTime'
   SEARCH_SELECTOR = '.searchInput'
 
   def _Login(self, action_runner):
     pandora_login.LoginAccount(action_runner, 'pandora', self.credentials_path)
 
   def _NavigateToMedia(self, action_runner):
     pass  # Audio autoplays on Pandora, no need to search.