Refactor stages 1, 2 and test_api overhaul.

scripts/slave/recipe_modules/chromium/api.py

Index: scripts/slave/recipe_modules/chromium/api.py
diff --git a/scripts/slave/recipe_modules/chromium/api.py b/scripts/slave/recipe_modules/chromium/api.py
index fe534cafe188c94860b11801f553a22b5f828e8a..12da8dec68ab0eb06f5fd0a56d30547b771afe68 100644
--- a/scripts/slave/recipe_modules/chromium/api.py
+++ b/scripts/slave/recipe_modules/chromium/api.py
@@ -312,7 +312,7 @@ class ChromiumApi(recipe_api.RecipeApi):
       full_args.append('--test-type=%s' % test_type)
     step_name = name or t_name
     full_args.append('--step-name=%s' % step_name)
-    if chartjson_file:
+    if chartjson_file and not 'step_test_data' in kwargs:
       full_args.append('--chartjson-file')
       full_args.append(self.m.json.output())
       kwargs['step_test_data'] = lambda: self.m.json.test_api.output([])
@@ -376,6 +376,9 @@ class ChromiumApi(recipe_api.RecipeApi):
     full_args.extend(args)
 
     runtest_path = self.package_repo_resource('scripts', 'slave', 'runtest.py')
+    test_data_kwargs = {key: kwargs[key]
+                        for key in ['step_test_data', 'stdout', 'stderr']
+                        if key in kwargs}
     if self.c.runtest_py.src_side and not disable_src_side_runtest_py:
       runtest_path = self.m.path['checkout'].join(
           'infra', 'scripts', 'runtest_wrapper.py')
@@ -386,7 +389,7 @@ class ChromiumApi(recipe_api.RecipeApi):
       step_name,
       runtest_path,
       full_args,
-      **kwargs
+      **test_data_kwargs
     )
 
   def sizes(self, results_url=None, perf_id=None, platform=None, **kwargs):