[tools/perf] Reference legacy_page_test module instead of page_test

tools/perf/measurements/page_cycler.py

 # Copyright 2012 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.
 
 """The page cycler measurement.
 
 This measurement registers a window load handler in which is forces a layout and
 then records the value of performance.now(). This call to now() measures the
 time from navigationStart (immediately after the previous page's beforeunload
 event) until after the layout in the page's load event. In addition, two garbage
 collections are performed in between the page loads (in the beforeunload event).
 This extra garbage collection time is not included in the measurement times.
 
 Finally, various memory and IO statistics are gathered at the very end of
 cycling all pages.
 """
 
 import collections
 import os
 
 from telemetry.core import util
-from telemetry.page import page_test
+from telemetry.page import legacy_page_test
 from telemetry.value import scalar
 
 from metrics import cpu
 from metrics import keychain_metric
 from metrics import memory
 from metrics import power
 from metrics import speedindex
 
 
-class PageCycler(page_test.PageTest):
+class PageCycler(legacy_page_test.LegacyPageTest):
 
   def __init__(self, page_repeat, pageset_repeat, cold_load_percent=50,
                report_speed_index=False, clear_cache_before_each_run=False):
     super(PageCycler, self).__init__(
         clear_cache_before_each_run=clear_cache_before_each_run)
 
     with open(os.path.join(os.path.dirname(__file__),
                            'page_cycler.js'), 'r') as f:
       self._page_cycler_js = f.read()
 
@@ skipping 104 matching lines @@
     # preserve any initial profile cache for as long as possible.
     # The second is that, if we did cold runs first, we'd have a transition
     # page set during which we wanted the run for each URL to both
     # contribute to the cold data and warm the catch for the following
     # warm run, and clearing the cache before the load of the following
     # URL would eliminate the intended warmup for the previous URL.
     return self._has_loaded_page[url] >= self._cold_run_start_index
 
   def DidRunPage(self, platform):
     self._power_metric.Close()