Nest multiple 'resolving hash xxx' steps under a single super step.

scripts/slave/recipe_modules/auto_bisect_staging/bisector.py

Index: scripts/slave/recipe_modules/auto_bisect_staging/bisector.py
diff --git a/scripts/slave/recipe_modules/auto_bisect_staging/bisector.py b/scripts/slave/recipe_modules/auto_bisect_staging/bisector.py
index 46cda11ec48eadf2b9759f3808b539f1460b8e71..4c92894ef42ed425ab8875cfba0914e3a8d2b229 100644
--- a/scripts/slave/recipe_modules/auto_bisect_staging/bisector.py
+++ b/scripts/slave/recipe_modules/auto_bisect_staging/bisector.py
@@ -538,7 +538,9 @@ class Bisector(object):
   def _revision_value_table(self):
     """Returns a string table showing revisions and their values."""
     header = [['Revision', 'Values']]
-    rows = [[r.revision_string(), str(r.debug_values)] for r in self.revisions]
+    with self._api.m.step.nest('Resolving hashes'):
+      rows = [[r.revision_string(), str(r.debug_values)]
+              for r in self.revisions]
     return self._pretty_table(header + rows)
 
   def _pretty_table(self, data):