[Telemetry] Measure power in tab_switching measurement

tools/perf/measurements/power_many_tabs.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.
+
+import time
+
+from metrics import power
+from telemetry.core import util
+from telemetry.page import page_measurement
+
+
+class PowerManyTabs(page_measurement.PageMeasurement):
+  """Load pageset in multiple tabs, measure power after quiesencence."""
+
+  # Amount of time to measure power usage for, in seconds.
+  POWER_MEAUSUREMENT_TIME_S = 5
+
+  def __init__(self, action_name_to_run=''):
+    super(PowerManyTabs, self).__init__(action_name_to_run=action_name_to_run)
+    self._power_metric = power.PowerMetric()
+
+  def CustomizeBrowserOptions(self, options):
+    power.PowerMetric.CustomizeBrowserOptions(options)
+
+  def TabForPage(self, page, browser):
+    return browser.tabs.New()
+
+  def StopBrowserAfterPage(self, browser, page):
+    # Restart browser after all pages in pageset are loaded.
+    return len(browser.tabs) == len(page.page_set.pages)
+
+  def MeasurePage(self, page, tab, results):
+    """Only measure on the last tab."""
+    if len(tab.browser.tabs) != len(page.page_set.pages):
+      return
+
+    util.WaitFor(tab.HasReachedQuiescence, 60)

[qsr, 2014/02/27 14:00:52]

Should you wait for the quiescence of every tab, and not just the last one?
I guess you could iterate over all tabs, keeping track of the total time spent
so as not to wait for more than one minute.

+
+    # Measure power after quiescence.
+    self._power_metric.Start(page, tab)
+    time.sleep(PowerManyTabs.POWER_MEAUSUREMENT_TIME_S)
+    self._power_metric.Stop(page, tab)
+
+    self._power_metric.AddResults(tab, results)