Port PerfWarm startup test to Telemetry

tools/perf/perf_tools/startup_tests.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 telemetry.page import page_benchmark
+
+# TODO(jeremy): Discard results from first iteration of warm tests.

[nduca, 2013/03/12 18:47:41]

This sounds like something you want to add as a feature of the page_benchmark or
page_runner system... e.g. copy the style of
needs_browser_restart_after_each_run.

[jeremy, 2013/03/13 08:16:53]

Agreed, will do so in followup patch.

+
+# Test how long Chrome takes to load when warm.
+class PerfWarm(page_benchmark.PageBenchmark):
+  def __init__(self):
+    super(PerfWarm, self).__init__(needs_browser_restart_after_each_run=True)
+
+  def CustomizeBrowserOptions(self, options):
+    options.AppendExtraBrowserArg('--dom-automation')
+    options.AppendExtraBrowserArg('--reduce-security-for-dom-automation-tests')
+
+  def MeasurePage(self, page, tab, results):
+    result = tab.EvaluateJavaScript(
+      'domAutomationController.getBrowserHistogram('

[nduca, 2013/03/12 18:47:41]

there's a file in perf_tools for accessing histograms cleanly, can you use that?

[jeremy, 2013/03/13 08:16:53]

The way i understand the code perf_tools/histogram_measurement is used to
subtract histograms and do all kinds of other fancy stuff.  I'd need to change
it to just get a plain histogram value here and I don't think we gain much but I
may very well be wrong.

+          '"Startup.BrowserMessageLoopStartTimeFromMainEntry")')
+    results.Add('startup_time', 'ms', result)