Avoid nesting steps called under waiting for x:

scripts/slave/recipes/bisect.py

 # Copyright 2015 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 base64
 import collections
 import json
 
 DEPS = [
     'auto_bisect',
     'recipe_engine/properties',
     'test_utils',
     'chromium_tests',
     'recipe_engine/raw_io',
     'recipe_engine/step',
     'halt',
     'recipe_engine/json',
 ]
 
 def RunSteps(api):
   mastername = api.m.properties.get('mastername')
   buildername = api.m.properties.get('buildername')
   # TODO(akuegel): Explicitly load the configs for the builders and don't rely
   # on builders.py in chromium_tests recipe module.
   bot_config = api.chromium_tests.create_bot_config_object(
       mastername, buildername)
   api.chromium_tests.configure_build(bot_config)
   api.m.chromium_tests.prepare_checkout(bot_config)
-  api.auto_bisect.perform_bisect()
+  api.auto_bisect.perform_bisect(do_not_nest_wait_for_revision=True)
 
 def GenTests(api):
   basic_test = api.test('basic')
   broken_bad_rev_test = api.test('broken_bad_revision_test')
   broken_good_rev_test = api.test('broken_good_revision_test')
   return_code_test = api.test('basic_return_code_test')
   basic_test += api.properties.generic(
       mastername='tryserver.chromium.perf',
       buildername='linux_perf_bisect')
   broken_bad_rev_test += api.properties.generic(
@@ skipping 225 matching lines @@
 
   if 'refrange' in revision_data:
     parent_step = 'Resolving reference range.'
     commit_pos = 'refs/heads/master@{#%s}' % commit_pos_number
     step_name = parent_step + 'crrev get commit hash for ' + commit_pos
     yield api.step_data(
         step_name,
         stdout=api.json.output({'git_sha': commit_hash}))
 
   if not skip_results:
-    step_name = ('Waiting for chromium@%s.gsutil '
-                 'Get test results for build %s') % (commit_hash[:10],
-                                                     commit_hash)
+    step_name = ('gsutil Get test results for build %s') % (commit_hash)
     if 'refrange' in revision_data:
       parent_step = 'Gathering reference values.'
     else:
       parent_step = 'Working on revision %s.' % ('chromium@' + commit_hash[:10])
       yield _get_post_bisect_step_data(api, parent_step)
     step_name = parent_step + step_name
     yield api.step_data(step_name, stdout=api.raw_io.output(json.dumps(
         test_results)))
 
     if 'cl_info' in revision_data:
       step_name = 'Reading culprit cl information.'
       stdout = api.json.output(revision_data['cl_info'])
       yield api.step_data(step_name, stdout=stdout)
 
 
 def _get_post_bisect_step_data(api, parent_step=''):
   """Gets step data for perf_dashboard/resource/post_json.py."""
   response = {'status_code': 200}
   return api.step_data(parent_step + 'Post bisect results',
                        stdout=api.json.output(response))