Make output placeholders like json.output index-able by name.

recipe_modules/json/example.py

Index: recipe_modules/json/example.py
diff --git a/recipe_modules/json/example.py b/recipe_modules/json/example.py
index 38b50d57b4eebccba0b0b21c802d72de25edb18c..ad0eca5b4504993d5d502f8bb244754cf9cc8ff3 100644
--- a/recipe_modules/json/example.py
+++ b/recipe_modules/json/example.py
@@ -37,9 +37,10 @@ def RunSteps(api):
       with open(sys.argv[2], 'w') as f:
         f.write(json.dumps(['x', 'y', %s]))
       """ % repr(FULLWIDTH_Z),
-      args=[api.json.output(), api.json.output()],
+      args=[api.json.output(name='1'), api.json.output(name='2')],
   )
-  assert result.json.output_all == [[1, 2, 3], ['x', 'y', FULLWIDTH_Z]]
+  assert result.json.outputs['1'] == [1, 2, 3]
+  assert result.json.outputs['2'] == ['x', 'y', FULLWIDTH_Z]
 
   example_dict = {'x': 1, 'y': 2}
 
@@ -66,6 +67,6 @@ def GenTests(api):
       api.step_data('echo1', stdout=api.json.output([1, 2, 3])) +
       api.step_data(
           'foo',
-          api.json.output([1, 2, 3]) +
-          api.json.output(['x', 'y', FULLWIDTH_Z]),
+          api.json.output([1, 2, 3], name='1') +
+          api.json.output(['x', 'y', FULLWIDTH_Z], name='2'),
       ))