Telemetry: Initialize smoothness and thread_times metrics before page load, not after.

tools/perf/measurements/smoothness_controller.py

Index: tools/perf/measurements/smoothness_controller.py
diff --git a/tools/perf/measurements/smoothness_controller.py b/tools/perf/measurements/smoothness_controller.py
index c054ccc6e2b03b8639ec7e7937175fbabdc4734e..6e8dcd9acead0a809ee674bad59ede024a9cec59 100644
--- a/tools/perf/measurements/smoothness_controller.py
+++ b/tools/perf/measurements/smoothness_controller.py
@@ -27,7 +27,7 @@ class SmoothnessController(object):
     self._tracing_timeline_data = None
     self._interaction = None
 
-  def Start(self, page, tab):
+  def SetUp(self, page, tab):
     # FIXME: Remove webkit.console when blink.console lands in chromium and
     # the ref builds are updated. crbug.com/386847
     custom_categories = ['webkit.console', 'blink.console', 'benchmark']
@@ -35,6 +35,8 @@ class SmoothnessController(object):
     tab.browser.StartTracing(','.join(custom_categories), 60)
     if tab.browser.platform.IsRawDisplayFrameRateSupported():
       tab.browser.platform.StartRawDisplayFrameRateMeasurement()
+
+  def Start(self, tab):
     # Start the smooth marker for all smooth actions.
     runner = action_runner.ActionRunner(tab)
     self._interaction = runner.BeginInteraction(