| # Copyright 2013 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 metrics import Metric |
| |
| class LoadingMetric(Metric): |
| """A metric for page loading time based entirely on window.performance""" |
| |
| def Start(self, page, tab): |
| raise NotImplementedError() |
| |
| def Stop(self, page, tab): |
| raise NotImplementedError() |
| |
| def AddResults(self, tab, results): |
| load_timings = tab.EvaluateJavaScript('window.performance.timing') |
| load_time_ms = ( |
| float(load_timings['loadEventStart']) - |
| load_timings['navigationStart']) |
| dom_content_loaded_time_ms = ( |
| float(load_timings['domContentLoadedEventStart']) - |
| load_timings['navigationStart']) |
| results.Add('load_time', 'ms', load_time_ms) |
| results.Add('dom_content_loaded_time', 'ms', |
| dom_content_loaded_time_ms) |
