Revert of Avoid nesting steps called under waiting for x:

scripts/slave/recipe_modules/auto_bisect/bisector.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 json
 import re
 import time
 import urllib
 
 from . import config_validation
@@ skipping 726 matching lines @@
       return True
     return False
 
   def wait_for_all(self, revision_list):
     """Waits for all revisions in list to finish."""
     for r in revision_list:
       self.wait_for(r)
 
   def wait_for(self, revision):
     """Waits for the revision to finish its job."""
-    while True:
-      revision.update_status()
-      if revision.in_progress:
-        self.api.m.python.inline(
-            'sleeping',
-            """
-            import sys
-            import time
-            time.sleep(20*60)
-            sys.exit(0)
-            """)
-      else:
-        break
+    with self.api.m.step.nest('Waiting for ' + revision.revision_string()):
+      while True:
+        revision.update_status()
+        if revision.in_progress:
+          self.api.m.python.inline(
+              'sleeping',
+              """
+              import sys
+              import time
+              time.sleep(20*60)
+              sys.exit(0)
+              """)
+        else:
+          break
 
   def _update_candidate_range(self):
     """Updates lkgr and fkbr (last known good/first known bad) revisions.
 
     lkgr and fkbr are 'pointers' to the appropriate RevisionState objects in
     bisectors.revisions."""
     for r in self.revisions:
       if r.tested:
         if r.good:
           self.lkgr = r
@@ skipping 169 matching lines @@
         })
     return revision_rows
 
   def _get_build_url(self):
     properties = self.api.m.properties
     bot_url = properties.get('buildbotURL',
                              'http://build.chromium.org/p/chromium/')
     builder_name = urllib.quote(properties.get('buildername', ''))
     builder_number = str(properties.get('buildnumber', ''))
     return '%sbuilders/%s/builds/%s' % (bot_url, builder_name, builder_number)