Add presubmit trybot for skia.

masters/master.client.skia.fyi/builders.cfg

 # Copyright 2014 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.
 
 builders = [
   { 'name': 'Housekeeper-PerCommit', 'recipe': 'skia/housekeeper_percommit' },
   { 'name': 'Housekeeper-Periodic-AutoRoll', 'recipe': 'skia/autoroll',
     'do_trybot': False, 'scheduler': 'skia_periodic_15mins',
     'cc': ['borenet@google.com'] },
   { 'name': 'Housekeeper-Nightly-RecreateSKPs_Canary',
     'recipe': 'skia/recreate_skps', 'do_trybot': False,
     'scheduler': 'skia_nightly' },
   { 'name': 'Housekeeper-Weekly-RecreateSKPs',
     'recipe': 'skia/recreate_skps', 'do_trybot': False,
     'scheduler': 'skia_weekly' },
   { 'name': 'Infra-PerCommit',
     'recipe': 'skia/infra',
     'scheduler': 'infra_percommit' },
+  { 'name': 'skia_presubmit',
+    'recipe': 'run_presubmit',
+    'properties': {
+      'repo_name': 'skia',
+    },
+    'do_trybot': True },

[borenet, 2015/05/12 16:33:50]

Just so you're aware, this will create two bots:
- skia_presubmit
- skia_presubmit-Trybot

That's fine with me - there's value in having a waterfall bot running the
presubmit.

[Adrian Kuegel, 2015/05/18 11:44:26]

I was not actually aware of this, I only wanted to create the
skia_presubmit-Trybot. But you are right, there is also value in having a
waterfall bot. And it looks to me like skia_master_utils.py does not allow to
create just a Trybot without the waterfall bot as well.

[borenet, 2015/05/18 12:05:49]

Yeah, the skia_master_utils were created under the assumption that we almost
always want to duplicate our waterfall bots as trybots.  I don't know that we've
ever needed to add a trybot that wasn't a clone of one of our waterfall bots.

 ]