[Telemetry] Add CanRunOnPlatform to story_runner and benchmark class.

telemetry/telemetry/story/expectations.py

 # Copyright 2017 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 logging
 
 
 class StoryExpectations(object):
   """An object that contains disabling expectations for benchmarks and stories.
 
@@ skipping 117 matching lines @@
     """
     for conditions, reason in self._expectations.get(story.name, []):
       for condition in conditions:
         if condition.ShouldDisable(platform, finder_options):
           logging.info('%s is disabled on %s due to %s.',
                        story.name, condition, reason)
           return reason
     return None
 
 
+# TODO(rnephew): Since TestConditions are being used for more than
+# just story expectations now, this should be decoupled and refactored
+# to be clearer.
 class _TestCondition(object):
   def ShouldDisable(self, platform, finder_options):
     raise NotImplementedError
 
   def __str__(self):
     raise NotImplementedError
 
 
 class _TestConditionByPlatformList(_TestCondition):
   def __init__(self, platforms, name):
@@ skipping 85 matching lines @@
     'W6210', 'Cherry Mobile Android One')
 ANDROID_SVELTE = _TestConditionAndroidSvelte()
 ANDROID_WEBVIEW = _TestConditionAndroidWebview()
 ANDROID_NOT_WEBVIEW = _TestConditionAndroidNotWebview()
 # MAC_10_11 Includes:
 #   Mac 10.11 Perf, Mac Retina Perf, Mac Pro 10.11 Perf, Mac Air 10.11 Perf
 MAC_10_11 = _TestConditionByMacVersion('10.11', 'Mac 10.11')
 # Mac 10_12 Includes:
 #   Mac 10.12 Perf, Mac Mini 8GB 10.12 Perf
 MAC_10_12 = _TestConditionByMacVersion('10.12', 'Mac 10.12')