[telemetry] Add page load interaction to V8.todomvc

tools/perf/page_sets/todomvc.py

Index: tools/perf/page_sets/todomvc.py
diff --git a/tools/perf/page_sets/todomvc.py b/tools/perf/page_sets/todomvc.py
index 5536c83f3fbbcd5742641fc88215c03413a90fd1..a7eaf09258d6ff57c074cd6c9e5f7b7cf095a46b 100644
--- a/tools/perf/page_sets/todomvc.py
+++ b/tools/perf/page_sets/todomvc.py
@@ -19,6 +19,8 @@ URL_LIST = [
     ('Vanilla JS', 'http://todomvc.com/examples/vanillajs'),
 ]
 
+INTERACTION_NAME = "Interaction.PageLoading"

[Sami, 2016/03/10 12:30:34]

nit: Single quote strings please.

+
 
 class TodoMVCPage(page_module.Page):
 
@@ -26,9 +28,20 @@ class TodoMVCPage(page_module.Page):
     super(TodoMVCPage, self).__init__(
         url=url, page_set=page_set, name=name,
         shared_page_state_class=shared_page_state.SharedDesktopPageState)
+    self.script_to_evaluate_on_commit = (
+        "console.time('" + INTERACTION_NAME + "');")

[Sami, 2016/03/10 12:30:34]

nit: How about creating an action_runner.Interaction() object and calling
Begin() here and End() in RunPageInteractions?

[jochen (gone - plz use gerrit), 2016/03/10 14:09:22]

there is no action runner that would live long enough for this to work.

there's also a more fundamental problem: We can't evaluate console.time() before
the iframe is completely setup, e.g. WindowProxy::initialize will always be
outside of this interaction

 
   def RunPageInteractions(self, action_runner):
-    pass
+    action_runner.ExecuteJavaScript(
+        """
+        this.hasRunRAF = 0;
+        requestAnimationFrame(function() {

[jochen (gone - plz use gerrit), 2016/03/10 11:41:45]

i wonder whether the page load interaction should end at the first frame, or
when the window.onload event fires

[Sami, 2016/03/10 12:30:34]

I'm wondering if both are a little early for some of the frameworks? I checked a
couple by placing a load breakpoint, and none of the pages had any real content
up at that point (even after waiting a few rAFs after onload). Maybe that's fine
if you mostly care about the parsing stage, but it might be worth coming up with
a way to stop only when there's something more meaningful on the screen.

You could also take a peek at a few traces to see if the interaction record
covers the area you care about.

[Camillo Bruni, 2016/03/10 12:30:55]

It should probably end with window.onLoad, since you probably get the first full
paint before?

[Camillo Bruni, 2016/03/10 15:12:53]

how about just waiting 4 seconds or so?

+            this.hasRunRAF = 1;
+            console.timeEnd('%s');
+        });
+        """ % INTERACTION_NAME
+    )
+    action_runner.WaitForJavaScriptCondition("this.hasRunRAF == 1")
 
 
 class TodoMVCPageSet(story.StorySet):