telemetry: Add rasterize_and_record benchmark for silk pages

tools/perf/benchmarks/rasterize_and_record.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 test
 
 from measurements import rasterize_and_record
 
 
 class RasterizeAndRecordTop25(test.Test):
   """Measures rasterize and record performance on the top 25 web pages.
 
   http://www.chromium.org/developers/design-documents/rendering-benchmarks"""
   test = rasterize_and_record.RasterizeAndRecord
   page_set = 'page_sets/top_25.json'
 
 
 class RasterizeAndRecordKeyMobileSites(test.Test):
   """Measures rasterize and record performance on the key mobile sites.
 
   http://www.chromium.org/developers/design-documents/rendering-benchmarks"""
   test = rasterize_and_record.RasterizeAndRecord
   page_set = 'page_sets/key_mobile_sites.json'
+
+
+class RasterizeAndRecordSilk(test.Test):
+  """Measures rasterize and record performance on the silk sites.
+
+  http://www.chromium.org/developers/design-documents/rendering-benchmarks"""
+  test = rasterize_and_record.RasterizeAndRecord
+  page_set = 'page_sets/key_silk_cases.json'