Add Wait* API to ActionRunner to wrap over WaitAction.

tools/perf/measurements/smoothness_unittest.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 sys
 
 from measurements import smoothness
 from telemetry.core import wpr_modes
 from telemetry.page import page
 from telemetry.page import page_measurement_unittest_base
 # pylint: disable=W0401,W0614
@@ skipping 16 matching lines @@
     self.category_filter = category_filter
 
 
 class AnimatedPage(page.Page):
   def __init__(self, page_set):
     super(AnimatedPage, self).__init__(
       url='file://animated_page.html',
       page_set=page_set, base_dir=page_set.base_dir)
 
   def RunSmoothness(self, action_runner):
-    action_runner.RunAction(WaitAction({'seconds': 1}))
+    action_runner.Wait(1)
 
 
 class FakeTab(object):
   def __init__(self):
     self.browser = FakeBrowser()
 
   def ExecuteJavaScript(self, js):
     pass
 
 class SmoothnessUnitTest(
@@ skipping 72 matching lines @@
     measurement = smoothness.Smoothness()
     results = self.RunMeasurement(measurement, ps, options=self._options)
     self.assertEquals(0, len(results.failures))
 
     mostly_smooth = results.FindAllPageSpecificValuesNamed('mostly_smooth')
     self.assertEquals(len(mostly_smooth), 1)
     self.assertGreaterEqual(mostly_smooth[0].GetRepresentativeNumber(), 0)
 
   def testCleanUpTrace(self):
     self.TestTracingCleanedUp(smoothness.Smoothness, self._options)