Add a smoothness benchmark with slimming paint enabled

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.
 
 from telemetry import benchmark
 
 from benchmarks import silk_flags
 from benchmarks import webgl_expectations
 from measurements import smoothness
 import page_sets
@@ skipping 84 matching lines @@
   http://www.chromium.org/developers/design-documents/rendering-benchmarks
   """
   test = smoothness.Smoothness
   page_set = page_sets.KeyMobileSitesSmoothPageSet
 
   @classmethod
   def Name(cls):
     return 'smoothness.key_mobile_sites_smooth'
 
 
+@benchmark.Disabled('mac', 'win', 'android')
+class SmoothnessKeyMobileSitesWithSlimmingPaint(benchmark.Benchmark):
+  """Measures smoothness on key mobile sites with --enable-slimming-paint.
+
+  http://www.chromium.org/developers/design-documents/rendering-benchmarks
+  """
+  test = smoothness.Smoothness
+  page_set = page_sets.KeyMobileSitesSmoothPageSet
+
+  def CustomizeBrowserOptions(self, options):
+    options.AppendExtraBrowserArgs(['--enable-slimming-paint'])
+
+  @classmethod
+  def Name(cls):
+    return 'smoothness.key_mobile_sites_with_slimming_paint_smooth'
+
+
 class SmoothnessToughAnimationCases(benchmark.Benchmark):
   test = smoothness.Smoothness
   page_set = page_sets.ToughAnimationCasesPageSet
 
   @classmethod
   def Name(cls):
     return 'smoothness.tough_animation_cases'
 
 
 @benchmark.Enabled('android')
@@ skipping 211 matching lines @@
     return 'smoothness.sync_scroll.pathological_mobile_sites'
 
 
 class SmoothnessToughAnimatedImageCases(benchmark.Benchmark):
   test = smoothness.Smoothness
   page_set = page_sets.ToughAnimatedImageCasesPageSet
 
   @classmethod
   def Name(cls):
     return 'smoothness.tough_animated_image_cases'