Add Wait* API to ActionRunner to wrap over WaitAction.

tools/perf/page_sets/tough_video_cases.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.
 # pylint: disable=W0401,W0614
 from telemetry.page.actions.all_page_actions import *
 from telemetry.page import page as page_module
 from telemetry.page import page_set as page_set_module
 
 
 class ToughVideoCasesPage(page_module.Page):
@@ skipping 28 matching lines @@
         'wait_for_ended': True
       }))
 
   def SeekBeforeAndAfterPlayhead(self, action_runner):
     action_runner.RunAction(PlayAction(
       {
         'wait_for_playing': True,
         'wait_for_ended': False
       }))
     # Wait for 1 second so that we know the play-head is at ~1s.
-    action_runner.RunAction(WaitAction(
-      {
-        'seconds': 1
-      }))
+    action_runner.Wait(1)
     # Seek to before the play-head location.
     action_runner.RunAction(SeekAction(
       {
         'seek_time': '0.5',
         'wait_for_seeked': True,
         'seek_label': 'seek_warm'
       }))
     # Seek to after the play-head location.
     action_runner.RunAction(SeekAction(
       {
@@ skipping 425 matching lines @@
     self.AddPage(Page20(self))
     self.AddPage(Page21(self))
     self.AddPage(Page22(self))
     self.AddPage(Page23(self))
     self.AddPage(Page24(self))
     self.AddPage(Page25(self))
     self.AddPage(Page26(self))
     self.AddPage(Page27(self))
     self.AddPage(Page28(self))
     self.AddPage(Page29(self))
-