Restore results of startup tests.

tools/perf/measurements/startup.py

Index: tools/perf/measurements/startup.py
diff --git a/tools/perf/measurements/startup.py b/tools/perf/measurements/startup.py
index be0c9711de569132ffed55572791f27a2eabb945..c9bb6b30a9dacc39e1ca465e70648b3ba982e60c 100644
--- a/tools/perf/measurements/startup.py
+++ b/tools/perf/measurements/startup.py
@@ -14,9 +14,9 @@ class Startup(page_measurement.PageMeasurement):
   tests, you should repeat the page set to ensure it's cached.
   """
 
-  def __init__(self):
+  def __init__(self, action_name_to_run = ''):
     super(Startup, self).__init__(needs_browser_restart_after_each_run=True,
-                                  action_name_to_run='navigate_steps')
+                                  action_name_to_run=action_name_to_run)
 
   def AddCommandLineOptions(self, parser):
     parser.add_option('--cold', action='store_true',
@@ -45,3 +45,19 @@ class Startup(page_measurement.PageMeasurement):
 
   def MeasurePage(self, page, 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')