Update page cycler to differenciate between cold and warm run by default.

tools/perf/measurements/page_cycler_unittest.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 unittest
 
 from measurements import page_cycler
 from telemetry.core import browser_options
 from telemetry.page import page_measurement_results
 from telemetry.unittest import simple_mock
 
@@ skipping 28 matching lines @@
   def setupCycler(self, args):
     cycler = page_cycler.PageCycler()
     options = browser_options.BrowserFinderOptions()
     parser = options.CreateParser()
     cycler.AddCommandLineOptions(parser)
     parser.parse_args(args)
     cycler.CustomizeBrowserOptions(options)
 
     return cycler
 
   def testOptionsColdLoadNoArgs(self):

[tonyg, 2013/11/06 18:31:49]

I find the code a little hard to follow. Could we add a test that confirms the
following (just to make sure my understanding is correct):

- PageSet with 2 URLs
- colod_load_percent is not passed in
- pageset_repeat is 3
- Verify that the first load of both URLs is reported as cold and the subsequent
2 loads of both URLs are reported as warm.

     cycler = self.setupCycler([])
 
-    self.assertFalse(cycler._cold_runs_requested)
-    self.assertEqual(cycler._number_warm_runs, 9)
+    self.assertEquals(cycler._cold_run_start_index, 10)
 
   def testOptionsColdLoadPagesetRepeat(self):
     cycler = self.setupCycler(['--pageset-repeat=20', '--page-repeat=2'])
 
-    self.assertFalse(cycler._cold_runs_requested)
-    self.assertEqual(cycler._number_warm_runs, 38)
+    self.assertEquals(cycler._cold_run_start_index, 40)
 
   def testOptionsColdLoadRequested(self):
     cycler = self.setupCycler(['--pageset-repeat=21', '--page-repeat=2',
                                '--cold-load-percent=40'])
 
-    self.assertTrue(cycler._cold_runs_requested)
-    self.assertEqual(cycler._number_warm_runs, 24)
+    self.assertEquals(cycler._cold_run_start_index, 26)
 
   def testIncompatibleOptions(self):
     exception_seen = False
     try:
       self.setupCycler(['--pageset-repeat=20s', '--page-repeat=2s',
                         '--cold-load-percent=40'])
     except Exception as e:
       exception_seen = True
       self.assertEqual('--cold-load-percent is incompatible with '
                        'timed repeat', e.args[0])
@@ skipping 47 matching lines @@
       results.WillMeasurePage(page)
       cycler.MeasurePage(page, tab, results)
       results.DidMeasurePage()
       self.assertEqual(num_results+1, len(results.page_results))
       result = results[-1]
       self.assertEqual(result.page, page)
       self.assertEqual(1, len(result.values))
       self.assertEqual(result.values[0].trace_name, 'page_load_time')
       self.assertEqual(result.values[0].units, 'ms')
       self.assertEqual(result.values[0].chart_name,
-                       'warm_times' if i < 3 else 'cold_times')
+                       'warm_times' if i > 0 and i < 3 else 'cold_times')
       cycler.DidNavigateToPage(page, tab)