[SP] Enable Slimming Paint by default in Chromium and Blink.

tools/perf/measurements/record_per_area.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 time
 
 from telemetry.page import page_test
 from telemetry.value import scalar
 
 from measurements import smoothness
 
 
 class RecordPerArea(page_test.PageTest):
   def __init__(self, start_wait_time=2):
     super(RecordPerArea, self).__init__(
         needs_browser_restart_after_each_page=True)
     self._start_wait_time = start_wait_time
 
   def CustomizeBrowserOptions(self, options):
     smoothness.Smoothness.CustomizeBrowserOptions(options)
     options.AppendExtraBrowserArgs([
         '--enable-impl-side-painting',
         '--enable-threaded-compositing',
-        '--enable-gpu-benchmarking'
+        '--enable-gpu-benchmarking',
+        # TODO(wkorman): Remove slimming paint disablement once we've sorted
+        # alternate testing. http://crbug.com/498936
+        '--disable-slimming-paint'

[aiolos (Not reviewing), 2015/06/11 19:49:11]

Two questions:

1) What are you trying to do with this change? Are you wanting to disable
slimming paint on all of the telemetry tests, or just the ones that use this
measurement?

2) Are you planning on using this measurement in tests? No one appears to be
using it in any benchmarks, and I was planning on deleting it.

     ])
 
   def ValidateAndMeasurePage(self, page, tab, results):
     # Wait until the page has loaded and come to a somewhat steady state.
     # Needs to be adjusted for every device (~2 seconds for workstation).
     time.sleep(self._start_wait_time)
 
     # Enqueue benchmark
     tab.ExecuteJavaScript("""
         window.benchmark_results = {};
@@ skipping 17 matching lines @@
     all_data = tab.EvaluateJavaScript('window.benchmark_results.results')
     for data in all_data:
       width = data['width']
       height = data['height']
       area = width * height
       time_ms = data['time_ms']
 
       results.AddValue(scalar.ScalarValue(
           results.current_page, 'area_%07d_%dx%d' % (area, width, height),
           'ms', time_ms))