copy the pica benchmark to polymer_load

tools/perf/measurements/polymer_load.py

+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+from telemetry.page.actions.all_page_actions import NavigateAction, WaitAction
+from telemetry.page import page
+from telemetry.page import page_measurement
+
+
+class PageForPolymerLoad(page.PageWithDefaultRunNavigate):
+
+  def __init__(self, url, page_set):
+    super(PageForPolymerLoad, self).__init__(
+      url=url,
+      page_set=page_set)
+    self.script_to_evaluate_on_commit = '''
+      document.addEventListener("polymer-ready", function() {
+        var unused = document.body.offsetHeight;
+        window.__polymer_ready_time = performance.now();
+        setTimeout(function() {
+          window.__polymer_ready = true;
+        }, 1000);
+      })
+    '''
+
+  def RunNavigateSteps(self, action_runner):
+    action_runner.RunAction(NavigateAction())
+    action_runner.RunAction(WaitAction(
+      {
+        'javascript': "window.__polymer_ready"
+      }))
+
+
+class PolymerLoadMeasurement(page_measurement.PageMeasurement):
+  def MeasurePage(self, _, tab, results):
+    result = int(tab.EvaluateJavaScript('__polymer_ready_time'))
+    results.Add('Total', 'ms', result)