Add a MotionMark smoothness benchmark.

tools/perf/benchmarks/smoothness.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 multiprocessing
 
 from core import perf_benchmark
 
 from benchmarks import silk_flags
 from measurements import smoothness
 import page_sets
@@ skipping 524 matching lines @@
   """Measures rendering statistics while scrolling advertisements."""
   page_set = page_sets.SyntheticToughWebglAdCasesPageSet
 
   @classmethod
   def Name(cls):
     return 'smoothness.tough_webgl_ad_cases'
 
   @classmethod
   def ShouldDisable(cls, possible_browser):
     return cls.IsSvelte(possible_browser)  # http://crbug.com/574485
+
+class SmoothnessMotionmark(_Smoothness):
+  """Measures frame rate and a variety of other statistics on MotionMark cases.
+  """
+  page_set = page_sets.MotionMarkPageSet
+
+  def SetExtraBrowserOptions(self, options):
+    options.AppendExtraBrowserArgs('--enable-experimental-canvas-features')
+
+  @classmethod
+  def Name(cls):
+    return 'smoothness.motionmark'