build: mark taskkill as an infra step

scripts/slave/recipe_modules/chromium/api.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 re
 
 from recipe_engine import recipe_api
 from recipe_engine import util as recipe_util
 
 class TestLauncherFilterFileInputPlaceholder(recipe_util.InputPlaceholder):
@@ skipping 634 matching lines @@
     # default on Mac and Linux, or if clang=1 is in GYP_DEFINES.  This step
     # is only needed on bots that use clang but where --if-needed doesn't update
     # clang. (In practice, this means on Windows when using gn, not gyp.)
     self.m.python(name='update_clang',
                   script=self.m.path['checkout'].join('tools', 'clang',
                                                       'scripts', 'update.py'))
 
   def taskkill(self):
     self.m.python(
       'taskkill',
-      self.package_repo_resource('scripts', 'slave', 'kill_processes.py'))
+      self.package_repo_resource('scripts', 'slave', 'kill_processes.py'),
+      infra_step=True)
 
   def cleanup_temp(self):
     self.m.python(
       'cleanup_temp',
       self.package_repo_resource('scripts', 'tools', 'runit.py'),
       ['--show-path',
        'python',
        self.package_repo_resource('scripts', 'slave', 'cleanup_temp.py')],
       infra_step=True)
 
@@ skipping 91 matching lines @@
       }))
 
   def get_annotate_by_test_name(self, test_name):
     return 'graphing'
 
   def download_lto_plugin(self):
     return self.m.python(
         name='download LTO plugin',
         script=self.m.path['checkout'].join(
             'build', 'download_gold_plugin.py'))