Add support for python pageset

tools/perf/benchmarks/page_cycler.py

 # Copyright (c) 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 measurements import page_cycler
 from telemetry import test
 
 
 class PageCyclerBloat(test.Test):
   test = page_cycler.PageCycler
@@ skipping 47 matching lines @@
 class PageCyclerMoz(test.Test):
   test = page_cycler.PageCycler
   page_set = 'page_sets/page_cycler/moz.json'
   options = {'pageset_repeat': 10}
 
 
 class PageCyclerNetsimTop10(test.Test):
   """Measures load time of the top 10 sites under simulated cable network."""
   tag = 'netsim'
   test = page_cycler.PageCycler
-  page_set = 'page_sets/top_10.json'
+  page_set = 'page_sets/top_10.py'
   options = {
     'cold_load_percent': 100,
     'extra_wpr_args': [
       '--shaping_type=proxy',
       '--net=cable'
       ],
     'pageset_repeat': 5,
     }
 
   def __init__(self):
@@ skipping 21 matching lines @@
   options = {'pageset_repeat': 10}
 
 
 # crbug.com/273986: This test is really flakey on xp.
 # cabug.com/341843: This test is always timing out on Android.
 @test.Disabled('android', 'win')
 class PageCyclerTypical25(test.Test):
   test = page_cycler.PageCycler
   page_set = 'page_sets/typical_25.json'
   options = {'pageset_repeat': 10}