Remove obsolete references to threaded-compositing and impl-side-painting flags.

tools/perf/measurements/smoothness.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 legacy_page_test
 from telemetry.timeline import chrome_trace_category_filter
 from telemetry.web_perf import timeline_based_measurement
 from telemetry.web_perf.metrics import smoothness
 
 
@@ skipping 52 matching lines @@
 
   def DidRunPage(self, platform):
     if self._tbm:
       self._tbm.DidRunStory(platform)
 
 
 class Repaint(Smoothness):
 
   def CustomizeBrowserOptions(self, options):
     options.AppendExtraBrowserArgs([
-        '--enable-impl-side-painting',
-        '--enable-threaded-compositing',
         '--enable-gpu-benchmarking'
     ])
 
 
 class SmoothnessWithRestart(Smoothness):
 
   def __init__(self):
     super(SmoothnessWithRestart, self).__init__(
         needs_browser_restart_after_each_page=True)