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

tools/perf/measurements/smoothness_unittest.py

Index: tools/perf/measurements/smoothness_unittest.py
diff --git a/tools/perf/measurements/smoothness_unittest.py b/tools/perf/measurements/smoothness_unittest.py
index e537399237661481f02e767b04604c9ba982a614..15c0c9caff9cabc87c5796801a40b913525c5c41 100644
--- a/tools/perf/measurements/smoothness_unittest.py
+++ b/tools/perf/measurements/smoothness_unittest.py
@@ -61,7 +61,7 @@ class SmoothnessUnitTest(
     tab = FakeTab()
     measurement = smoothness.Smoothness()
     measurement.WillStartBrowser(tab.browser)
-    measurement.WillRunActions(test_page, tab)
+    measurement.WillNavigateToPage(test_page, tab)

[picksi, 2014/07/18 11:30:58]

Are we just moving this problem to somewhere else for a future developer to run
into? Is there other work being done in WillRunActions that we are now failing
to do (or will fail to do in the future as the code grows)? I can't think of an
easy solution here, as we are relying on an unexpected side effect of a function
(i.e. starting the metric stuff)... :)

[Dominik Grewe, 2014/07/18 16:10:51]

How about we call both? :) That's what's happening inside Telemetry and it means
we don't need to know what happens when. (And I need it for the test to pass in
my new patch set...)

[picksi, 2014/07/18 16:47:20]

Can it safely be doubly initialized without losing the data recorded between 1st
init and 2nd init?

Would it be too big and scary to make the whole thing lazily initialize, so it
gets initialized the first time it is used? Is there some sort of singleton at
the bottom of this?

 
     expected_category_filter = [
         'DELAY(cc.BeginMainFrame;0.012000;static)',