Add Wait* API to ActionRunner to wrap over WaitAction.

tools/perf/page_sets/tough_scheduling_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 ToughSchedulingCasesPage(page_module.Page):
@@ skipping 273 matching lines @@
 class Page19(ToughSchedulingCasesPage):
 
   """ Why: Both main and impl thread animating concurrently """
 
   def __init__(self, page_set):
     super(Page19, self).__init__(
       url='file://tough_scheduling_cases/split_animation.html',
       page_set=page_set)
 
   def RunSmoothness(self, action_runner):
-    action_runner.RunAction(WaitAction(
-      {
-        "seconds": 3
-      }))
+    action_runner.Wait(3)
 
 class Page20(ToughSchedulingCasesPage):
 
   """ Why: Simple JS touch dragging """
 
   def __init__(self, page_set):
     super(Page20, self).__init__(
       url='file://tough_scheduling_cases/simple_touch_drag.html',
       page_set=page_set)
 
@@ skipping 133 matching lines @@
       bounce=True,
       page_set=self))
     # Why: Scroll bounce with slow handler on desktop, blocks only once until
     # ACK timeout.
     self.AddPage(EmptyTouchHandlerPage(
       name='bounce_desktop_slow_handler',
       desktop=True,
       slow_handler=True,
       bounce=True,
       page_set=self))
-