[Telemetry] Add power usage metric

tools/perf/measurements/startup.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 metrics import power
 from metrics import startup_metric
 from telemetry.page import page_measurement
 
 class Startup(page_measurement.PageMeasurement):
   """Performs a measurement of Chromium's startup performance.
 
   This test must be invoked with either --warm or --cold on the command line. A
   cold start means none of the Chromium files are in the disk cache. A warm
   start assumes the OS has already cached much of Chromium's content. For warm
   tests, you should repeat the page set to ensure it's cached.
   """
 
   def __init__(self, action_name_to_run = ''):
     super(Startup, self).__init__(needs_browser_restart_after_each_run=True,
                                   action_name_to_run=action_name_to_run)
+    self._power_metric = None

[tonyg, 2014/01/23 18:23:40]

startup represents such a fleeting period that it isn't clear to me whether
there is value in measuring our efficiency during startup.

I suggested some metrics which I do think benefit from power measurement here:
https://code.google.com/p/chromium/issues/detail?id=336672

But perhaps we want to use the metric in a follow-up CL just in case something
breaks, then we don't have to worry about reverting the Metric itself.

[jeremy, 2014/01/23 18:58:41]

Done.

 
   def AddCommandLineOptions(self, parser):
     parser.add_option('--cold', action='store_true',
                       help='Clear the OS disk cache before performing the test')
     parser.add_option('--warm', action='store_true',
                       help='Start up with everything already cached')
 
   def CustomizeBrowserOptions(self, options):
     # TODO: Once the bots start running benchmarks, enforce that either --warm
     # or --cold is explicitly specified.
     # assert options.warm != options.cold, \
     #     "You must specify either --warm or --cold"
     if options.cold:
       browser_options = options.browser_options
       browser_options.clear_sytem_cache_for_browser_and_profile_on_start = True
     else:
       self.discard_first_result = True
 
     options.AppendExtraBrowserArgs([
         '--enable-stats-collection-bindings'
     ])
 
   def RunNavigateSteps(self, page, tab):
     # Overriden so that no page navigation occurs - startup to the NTP.
     pass
 
+  def WillStartBrowser(self, browser):
+    self._power_metric = power.PowerMetric()
+    self._power_metric.Start(None, None)
+
   def MeasurePage(self, page, tab, results):
+    self._power_metric.Stop(None, None)
+    self._power_metric.AddResults(tab, results)
     startup_metric.StartupMetric().AddResults(tab, results)
 
 
 class StartWithUrl(Startup):
   """Performs a measurement of Chromium's performance starting with a URL.
 
   This test must be invoked with either --warm or --cold on the command line. A
   cold start means none of the Chromium files are in the disk cache. A warm
   start assumes the OS has already cached much of Chromium's content. For warm
   tests, you should repeat the page set to ensure it's cached.
 
   The startup URL is taken from the page set's set_startup_url action. This
   allows the testing of multiple different URLs in a single benchmark.
   """
 
   def __init__(self):
-    super(StartWithUrl, self).__init__(action_name_to_run='navigate_steps')
+    super(StartWithUrl, self).__init__(action_name_to_run='navigate_steps')