[Telemetry] Improve elevate_privilege handling in LaunchApplication() + Fix killing of power metri…

tools/perf/benchmarks/benchmark_smoke_unittest.py

 # Copyright 2014 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.
 
 """Run the first page of one benchmark for every module.
 
 Only benchmarks that have a composable measurement are included.
 Ideally this test would be comprehensive, however, running one page
 of every benchmark would run impractically long.
 """
 
 import os
 import unittest
 
 from telemetry import benchmark as benchmark_module
 from telemetry.core import discover
 from telemetry.page import page_test
 from telemetry.unittest_util import options_for_unittests
 from telemetry.unittest_util import progress_reporter
 
 
 def SmokeTestGenerator(benchmark):
   # NOTE TO SHERIFFS: DO NOT DISABLE THIS TEST.
   #
   # This smoke test dynamically tests all benchmarks. So disabling it for one
   # failing or flaky benchmark would disable a much wider swath of coverage
   # than is usally intended. Instead, if a particular benchmark is failing,
   # disable it in tools/perf/benchmarks/*.
-
-  # EXCEPTIONS TO THE ABOVE RULE: crbug.com/351114, crbug.com/423688
-  @benchmark_module.Disabled('chromeos', 'mavericks')
+  @benchmark_module.Disabled('chromeos')  # crbug.com/351114
   def BenchmarkSmokeTest(self):
     # Only measure a single page so that this test cycles reasonably quickly.
     benchmark.options['pageset_repeat'] = 1
     benchmark.options['page_repeat'] = 1
 
     class SinglePageBenchmark(benchmark):  # pylint: disable=W0232
       def CreatePageSet(self, options):
         # pylint: disable=E1002
         ps = super(SinglePageBenchmark, self).CreatePageSet(options)
         for p in ps.pages:
@@ skipping 65 matching lines @@
     # in a class, and then throw the ones we don't need away instead.
     if hasattr(benchmark, '_enabled_strings'):
       method._enabled_strings = benchmark._enabled_strings
     if hasattr(benchmark, '_disabled_strings'):
       method._disabled_strings = benchmark._disabled_strings
     setattr(BenchmarkSmokeTest, benchmark.Name(), method)
 
     suite.addTest(BenchmarkSmokeTest(benchmark.Name()))
 
   return suite