Add simple depends_on API.

recipes.py

Index: recipes.py
diff --git a/recipes.py b/recipes.py
index 5c4c67760d25013cc4593d0916f4676b608035e5..6e1ed31caeac7ac75dc9b9e8d995562ee375e20e 100755
--- a/recipes.py
+++ b/recipes.py
@@ -31,7 +31,12 @@ def get_package_config(args):
 
 def simulation_test(package_deps, args):
   from recipe_engine import simulation_test
-  simulation_test.main(package_deps, args=json.loads(args.args))
+  from recipe_engine import loader
+
+  _, config_file = get_package_config(args)
+  universe = loader.RecipeUniverse(package_deps, config_file.path)
+
+  simulation_test.main(universe, args=json.loads(args.args))
 
 
 def lint(package_deps, args):
@@ -46,9 +51,8 @@ def handle_recipe_return(recipe_result, result_filename, stream):
       if result_filename:
         with open(result_filename, 'w') as f:
           f.write(result_string)
-      else:
-        with stream.step('recipe result') as s:
-          s.write_log_lines('result', [result_string])
+      with stream.step('recipe result') as s:
+        s.write_log_lines('result', [result_string])
 
     if 'reason' in recipe_result.result:
       with stream.step('recipe failure reason') as s:
@@ -101,7 +105,8 @@ def run(package_deps, args):
   os.environ['PYTHONUNBUFFERED'] = '1'
   os.environ['PYTHONIOENCODING'] = 'UTF-8'
 
-  universe = loader.RecipeUniverse(package_deps)
+  _, config_file = get_package_config(args)
+  universe = loader.RecipeUniverse(package_deps, config_file.path)
 
   workdir = (args.workdir or
       os.path.join(os.path.dirname(os.path.realpath(__file__)), 'workdir'))
@@ -115,7 +120,6 @@ def run(package_deps, args):
 
   try:
     ret = recipe_run.run_steps(properties, stream, universe=universe)
-
   finally:
     os.chdir(old_cwd)