[Telemetry] Add the ability to flush the system file cache to platform.

tools/telemetry/telemetry/core/perf_tests_helper.py

 # Copyright (c) 2012 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 __future__ import absolute_import
 
 import os
 import sys
 
 def __init__():
   path = os.path.join(os.path.dirname(__file__),
                       '..', '..', '..', '..', 'build', 'android')
   path = os.path.abspath(path)
   assert os.path.exists(os.path.join(path,
                                      'pylib', '__init__.py'))
   if path not in sys.path:
     sys.path.append(path)
 
 __init__()
 
 from pylib import perf_tests_helper # pylint: disable=F0401
+CacheControl = \
+    perf_tests_helper.CacheControl

[dtu, 2013/07/29 22:19:28]

Oh, that's why :)

Uhm, this method is Android-specific, so it's better to not make it available
here. android/pylib/perf_tests_helper is already imported by
android_platform_backend, so you can just use that directly.

 GeomMeanAndStdDevFromHistogram = \
     perf_tests_helper.GeomMeanAndStdDevFromHistogram
 PrintPerfResult = \
     perf_tests_helper.PrintPerfResult
 PrintPages = \
     perf_tests_helper.PrintPages