Add a Telemetry based cold startup test.

tools/perf/measurements/startup_warm.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.
-
-import json
-
-from telemetry.page import page_measurement
-
-
-class StartupWarm(page_measurement.PageMeasurement):
-  """Test how long Chrome takes to load when warm."""
-  HISTOGRAMS_TO_RECORD = {
-    'messageloop_start_time' :
-        'Startup.BrowserMessageLoopStartTimeFromMainEntry',
-    'window_display_time' : 'Startup.BrowserWindowDisplay',
-    'open_tabs_time' : 'Startup.BrowserOpenTabs'}
-
-  def __init__(self):
-    super(StartupWarm, self).__init__(needs_browser_restart_after_each_run=True,
-                                      discard_first_result=True)
-
-  def CustomizeBrowserOptions(self, options):
-    options.AppendExtraBrowserArg('--enable-stats-collection-bindings')
-
-    # Old commandline flags used for reference builds.
-    options.AppendExtraBrowserArg('--dom-automation')
-    options.AppendExtraBrowserArg(
-          '--reduce-security-for-dom-automation-tests')
-
-  def MeasurePage(self, page, tab, results):
-    # TODO(jeremy): Remove references to
-    # domAutomationController.getBrowserHistogram when we update the reference
-    # builds.
-    get_histogram_js = ('(window.statsCollectionController ?'
-        'statsCollectionController :'
-        'domAutomationController).getBrowserHistogram("%s")')
-
-
-    for display_name, histogram_name in self.HISTOGRAMS_TO_RECORD.iteritems():
-      result = tab.EvaluateJavaScript(get_histogram_js % histogram_name)
-      result = json.loads(result)
-      measured_time = 0
-
-      if 'sum' in result:
-        # For all the histograms logged here, there's a single entry so sum
-        # is the exact value for that entry.
-        measured_time = result['sum']
-      elif 'buckets' in result:
-        measured_time = \
-            (result['buckets'][0]['high'] + result['buckets'][0]['low']) / 2
-
-      results.Add(display_name, 'ms', measured_time)