Minor cleanup of some recipe framework code.

scripts/slave/recipe_modules/step_history/api.py

Index: scripts/slave/recipe_modules/step_history/api.py
diff --git a/scripts/slave/recipe_modules/step_history/api.py b/scripts/slave/recipe_modules/step_history/api.py
index 9875dc712bc3056c1e0b507489e90118e09831bd..788384a1ac61df31e99a131d78c1777bfe3c8e2e 100644
--- a/scripts/slave/recipe_modules/step_history/api.py
+++ b/scripts/slave/recipe_modules/step_history/api.py
@@ -18,6 +18,9 @@ class StepHistoryApi(recipe_api.RecipeApi, collections.Mapping):
 
   def __init__(self, step_history, **kwargs):
     super(StepHistoryApi, self).__init__(**kwargs)
+    # step_history is instantiated in annontated_run.py. Recipe engine is

[Vadim Sh., 2014/03/05 06:09:30]

That was non obvious dependency for me. Also added and assert as a type hint.
OrderedDict is crucial since we rely on order in last_step.

[iannucci, 2014/03/05 20:43:37]

Oh, yeah, this is the other thing that we pass via kwargs in load_module. Can
you make it a kwarg though, since it's meant to be used by name?

Can't wait to get rid of this module...

[Vadim Sh., 2014/03/05 21:40:38]

What do you mean? kwargs.get('step_history')? Than same should be done in
'properties' module. Not sure it improves readability.

+    # responsible for updating it.
+    assert isinstance(step_history, collections.OrderedDict)
     self._step_history = step_history
 
   def __getitem__(self, key):