telemetry: Allow page tests to be configured via constructor

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 6d26ee92a1a1b00e43ea42752d15bb2a18366dd9..dce938aa56a982dbe4e0437c4616a7502ec1fb54 100644
--- a/tools/perf/measurements/startup.py
+++ b/tools/perf/measurements/startup.py
@@ -18,17 +18,16 @@ class Startup(page_test.PageTest):
   def __init__(self, action_name_to_run = ''):
     super(Startup, self).__init__(needs_browser_restart_after_each_page=True,
                                   action_name_to_run=action_name_to_run)
+    self._cold = False
 
-  @classmethod
-  def AddCommandLineArgs(cls, parser):
+  def AddCommandLineArgs(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')
 
-  @classmethod
-  def ProcessCommandLineArgs(cls, parser, args):
-    cls._cold = args.cold
+  def ProcessCommandLineArgs(self, parser, args):
+    self._cold = args.cold
     # TODO: Once the bots start running benchmarks, enforce that either --warm
     # or --cold is explicitly specified.
     # if args.warm == args.cold: