Refactor the way that TestApi works so that it is actually useful.

scripts/slave/recipes/run_presubmit.py

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 DEPS = [
   'gclient',
   'git',
   'path',
   'properties',
   'rietveld',
@@ skipping 32 matching lines @@
     '--skip_canned', 'CheckRietveldTryJobExecution',
     '--skip_canned', 'CheckTreeIsOpen',
     '--skip_canned', 'CheckBuildbotPendingBuilds',
     '--rietveld_url', api.properties['rietveld'],
     '--rietveld_email', '',  # activates anonymous mode
     '--rietveld_fetch'])
 
 
 def GenTests(api):
   for repo_name in ['blink', 'blink_bare', 'tools_build', 'chromium']:
+    extra = {}
     if 'blink' in repo_name:
-      props = api.properties_tryserver(
-        root='src/third_party/WebKit'
-      )
-    else:
-      props = api.properties_tryserver()
+      extra['root'] = 'src/third_party/WebKit'
 
-    props['repo_name'] = repo_name
-    yield repo_name, {
-      'properties': props
-    }
+    yield api.Test(repo_name) + api.properties.tryserver(
+      repo_name=repo_name,
+      **extra
+    )