[system-health] Tear down the browser after each story in system_health.memory_*

tools/perf/benchmarks/system_health.py

 # Copyright 2016 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 re
 
 from core import perf_benchmark
 from telemetry import benchmark
 from telemetry.timeline import chrome_trace_category_filter
 from telemetry.web_perf import timeline_based_measurement
 import page_sets
 
 
 # See tr.v.Numeric.getSummarizedScalarNumericsWithNames()
 # https://github.com/catapult-project/catapult/blob/master/tracing/tracing/value/numeric.html#L323
 _IGNORED_STATS_RE = re.compile(r'_(std|count|max|min|sum|pct_\d{4}(_\d+)?)$')
 
 
 class _SystemHealthBenchmark(perf_benchmark.PerfBenchmark):

[nednguyen, 2016/07/21 20:08:50]

I forgot to comment, why not override ShouldTearDownStateAfterEachStoryRun here
so that it applies to all system health benchmark by default?

[petrcermak, 2016/07/22 19:37:12]

I decided not to do that because _MemorySystemHealthBenchmark currently doesn't
inherit from _SystemHealthBenchmark (and I didn't want to change it in this
patch because other methods would be inherited as well). Also note that all
subclasses of _SystemHealthBenchmark are globally disabled.

   TRACING_CATEGORIES = [
     'benchmark',
     'navigation',
     'blink.user_timing',
   ]
 
   def CreateTimelineBasedMeasurementOptions(self):
     options = timeline_based_measurement.Options()
     options.config.chrome_trace_config.SetCategoryFilter(
         chrome_trace_category_filter.ChromeTraceCategoryFilter(','.join(
@@ skipping 46 matching lines @@
             '-*,disabled-by-default-memory-infra'))
     options.config.enable_android_graphics_memtrack = True
     options.SetTimelineBasedMetrics(['memoryMetric'])
     return options
 
   def CreateStorySet(self, options):
     return page_sets.SystemHealthStorySet(platform=self.PLATFORM,
                                           take_memory_measurement=True)
 
   @classmethod
+  def ShouldTearDownStateAfterEachStoryRun(cls):
+    return True
+
+  @classmethod
   def Name(cls):
     return 'system_health.memory_%s' % cls.PLATFORM
 
   @classmethod
   def ValueCanBeAddedPredicate(cls, value, is_first_result):
     # TODO(crbug.com/610962): Remove this stopgap when the perf dashboard
     # is able to cope with the data load generated by TBMv2 metrics.
     return not _IGNORED_STATS_RE.search(value.name)
 
 
@@ skipping 41 matching lines @@
     options.config.atrace_config.app_name = 'org.chromium.webview_shell'
     return options
 
   @classmethod
   def ShouldTearDownStateAfterEachStoryRun(cls):
     return True
 
   @classmethod
   def Name(cls):
     return 'system_health.webview_startup'