telemetry: Delete loading measurement.

tools/perf/measurements/loading_trace.py

-# 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 measurements import timeline_controller
-from metrics import loading
-from metrics import timeline
-from telemetry.page import page_test
-from telemetry.web_perf import timeline_interaction_record as tir_module
-
-class LoadingTrace(page_test.PageTest):
-  def __init__(self, *args, **kwargs):
-    super(LoadingTrace, self).__init__(*args, **kwargs)
-    self._timeline_controller = timeline_controller.TimelineController()
-
-  def WillNavigateToPage(self, page, tab):
-    self._timeline_controller.SetUp(page, tab)
-    self._timeline_controller.Start(tab)
-
-  def ValidateAndMeasurePage(self, page, tab, results):
-    # In current telemetry tests, all tests wait for DocumentComplete state,
-    # but we need to wait for the load event.
-    tab.WaitForJavaScriptExpression('performance.timing.loadEventStart', 300)
-
-    # TODO(nduca): when crbug.com/168431 is fixed, modify the page sets to
-    # recognize loading as a toplevel action.
-    self._timeline_controller.Stop(tab)
-
-    loading.LoadingMetric().AddResults(tab, results)
-    timeline_metric = timeline.LoadTimesTimelineMetric()
-    renderer_thread = \
-        self._timeline_controller.model.GetRendererThreadFromTabId(tab.id)
-    record = tir_module.TimelineInteractionRecord(
-      "loading_trace_interaction", 0, float('inf'))
-    timeline_metric.AddResults(
-      self._timeline_controller.model,
-      renderer_thread,
-      [record],
-      results)
-
-  def CleanUpAfterPage(self, _, tab):
-    self._timeline_controller.CleanUp(tab)