[tools/perf] Reference legacy_page_test module instead of page_test

tools/perf/measurements/draw_properties.py

 # Copyright 2015 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 telemetry.timeline import model
 from telemetry.timeline import tracing_config
 from telemetry.value import scalar
 
 
-class DrawProperties(page_test.PageTest):
+class DrawProperties(legacy_page_test.LegacyPageTest):
 
   def __init__(self):
     super(DrawProperties, self).__init__()
 
   def CustomizeBrowserOptions(self, options):
     options.AppendExtraBrowserArgs([
         '--enable-prefer-compositing-to-lcd-text',
     ])
 
   def WillNavigateToPage(self, page, tab):
@@ skipping 22 matching lines @@
         'LayerTreeHostCommon::ComputeVisibleRectsWithPropertyTrees')
 
     results.AddValue(scalar.ScalarValue(
         results.current_page, 'PT_avg_cost', 'ms', pt_avg,
         description='Average time spent processing property trees'))
 
   def DidRunPage(self, platform):
     tracing_controller = platform.tracing_controller
     if tracing_controller.is_tracing_running:
       tracing_controller.StopTracing()