Disable smoothness.tough_webgl_cases on Mac since it is failing: http://build.chromium.org/p/chromi…

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 benchmarks import silk_flags
 import page_sets
 from measurements import smoothness
 from telemetry import benchmark
 
 
 class SmoothnessTop25(benchmark.Benchmark):
   """Measures rendering statistics while scrolling down the top 25 web pages.
 
   http://www.chromium.org/developers/design-documents/rendering-benchmarks"""
   test = smoothness.Smoothness
   page_set = page_sets.Top25PageSet
 
 
 @benchmark.Disabled('mac')  # crbug.com/388877
 class SmoothnessToughCanvasCases(benchmark.Benchmark):
   test = smoothness.Smoothness
   page_set = page_sets.ToughCanvasCasesPageSet
 
 
-@benchmark.Disabled('android')  # crbug.com/373812
+@benchmark.Disabled('android', 'mac')  # crbug.com/373812
 class SmoothnessToughWebGLCases(benchmark.Benchmark):
   test = smoothness.Smoothness
   page_set = page_sets.ToughWebglCasesPageSet
 
 
 class SmoothnessMaps(benchmark.Benchmark):
   test = smoothness.Smoothness
   page_set = page_sets.MapsPageSet
 
 
@@ skipping 123 matching lines @@
   """Measures rendering statistics for the Polymer cases with GPU rasterization
   using bleeding edge rendering fast paths.
   """
   tag = 'fast_path_gpu_rasterization'
   test = smoothness.Smoothness
   page_set = page_sets.PolymerPageSet
   def CustomizeBrowserOptions(self, options):
     super(SmoothnessFastPathGpuRasterizationPolymer, self). \
         CustomizeBrowserOptions(options)
     silk_flags.CustomizeBrowserOptionsForFastPath(options)