[tools/perf] Reference legacy_page_test module instead of page_test

tools/perf/measurements/media.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 telemetry.page import page_test
+from telemetry.page import legacy_page_test
 
 from metrics import cpu
 from metrics import media
 from metrics import power
 from metrics import system_memory
 
 
-class Media(page_test.PageTest):
+class Media(legacy_page_test.LegacyPageTest):
   """The MediaMeasurement class gathers media-related metrics on a page set.
 
   Media metrics recorded are controlled by metrics/media.js.  At the end of the
   test each metric for every media element in the page are reported.
   """
 
   def __init__(self):
     super(Media, self).__init__()
     self._media_metric = None
     # Used to add browser power and CPU metrics to results per test.
@@ skipping 40 matching lines @@
       self._cpu_metric.AddResults(tab, results, trace_name=trace_name)
       exclude_metrics = ['WorkingSetSizePeak', 'SystemCommitCharge', 'VMPeak',
                          'VM']
       self._memory_metric.AddResults(tab, results,
                                      trace_name=trace_name,
                                      exclude_metrics=exclude_metrics)
       self._power_metric.AddResults(tab, results)
 
   def DidRunPage(self, platform):
     self._power_metric.Close()