mac: Expose keychain access frequency to Telemetry.

tools/perf/measurements/memory_pressure.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.
 
 """Multi tab memory test.
 
 This test is a multi tab test, but we're interested in measurements for
 the entire test rather than each single page.
 """
 
 import logging
 
+from measurements import PageTestMeasurement
 from telemetry.value import histogram_util
-from telemetry.page import page_test
 
 
-class MemoryPressure(page_test.PageTest):
+class MemoryPressure(PageTestMeasurement):
   def __init__(self, *args, **kwargs):
     super(MemoryPressure, self).__init__(*args, **kwargs)
     # _first_tab is used to access histograms
     self._is_first_page = True
     self._tab_count = 0
 
   # Allow histogram collection
   def CustomizeBrowserOptions(self, options):
+    super(MemoryPressure, self).CustomizeBrowserOptions(options)
     histogram_util.CustomizeBrowserOptions(options)
 
   # Open a new tab at each page
   def TabForPage(self, page, browser):
     return browser.tabs.New()
 
   def GetTabsHistogramCounts(self, tab):
     histogram_type = histogram_util.BROWSER_HISTOGRAM
     discard_count = histogram_util.GetHistogramCount(
       histogram_type, "Tabs.Discard.DiscardCount", tab)
     kill_count = histogram_util.GetHistogramCount(
       histogram_type, "Tabs.SadTab.KillCreated", tab)
     return (discard_count, kill_count)
 
   def ValidateAndMeasurePage(self, page, tab, results):
+    super(MemoryPressure, self).ValidateAndMeasurePage(page, tab, results)
+
     # After navigating to each page, check if it triggered tab discards or
     # kills.
     (discard_count, kill_count) = self.GetTabsHistogramCounts(tab)
 
     # Sanity check for first page
     if self._is_first_page:
       self._is_first_page = False
       assert discard_count == 0 and kill_count == 0
 
     self._tab_count += 1
     # End the test at the first kill or discard.
     if kill_count > 0 or discard_count > 0:
       logging.info("test ending at tab %d, discards = %d, kills = %d" %
         (self._tab_count, discard_count, kill_count))
       self.RequestExit()