[telemetry] Sort imports in Telemetry and its dependents.

tools/perf/measurements/session_restore.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.
 
 import collections
 
+from telemetry.core import util
+from telemetry.value import histogram
+from telemetry.value import histogram_util
+
 from measurements import startup
 from metrics import cpu
 from metrics import startup_metric
-from telemetry.core import util
-from telemetry.value import histogram
-from telemetry.value import histogram_util
+
 
 _HISTOGRAMS = [
     {
         'name': 'SessionRestore.ForegroundTabFirstLoaded',
         'display_name': 'SessionRestore_ForegroundTabFirstLoaded',
     },
     {
         'name': 'SessionRestore.AllTabsLoaded',
         'display_name': 'SessionRestore_AllTabsLoaded',
     },
@@ skipping 49 matching lines @@
     self._cpu_metric.Stop(None, None)
     self._cpu_metric.AddResults(tab, results, 'cpu_utilization')
 
     for h in _HISTOGRAMS:
       histogram_data = histogram_util.GetHistogram(
           histogram_util.BROWSER_HISTOGRAM, h['name'], tab)
 
       results.AddValue(histogram.HistogramValue(
           page, h['display_name'], 'ms', raw_value_json=histogram_data,
           important=False))