Pass buildbucket.build.id to cbuildbot as --buildbucket-id.

scripts/slave/recipes/cros/cbuildbot_tryjob.py

Index: scripts/slave/recipes/cros/cbuildbot_tryjob.py
diff --git a/scripts/slave/recipes/cros/cbuildbot_tryjob.py b/scripts/slave/recipes/cros/cbuildbot_tryjob.py
index 5c3e8ab3d79f06ff309e8dd60081bceb9c559e12..0127fe98be408d2121a6bdd74b6b2dd854300bf9 100644
--- a/scripts/slave/recipes/cros/cbuildbot_tryjob.py
+++ b/scripts/slave/recipes/cros/cbuildbot_tryjob.py
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import base64
+import json

[dnj (Google), 2016/07/20 01:37:06]

(Same w/ JSON recipe module)

 import zlib
 
 
@@ -177,3 +178,20 @@ def GenTests(api):
       )
       + api.chromite.seed_chromite_config(_CHROMITE_CONFIG)
   )
+
+  # Test a config with buildbucket properties
+  yield (
+      api.test('pre_cq_buildbucket_config')
+      + api.properties(
+          mastername='chromiumos.tryserver',
+          buildername='pre-cq',
+          slavename='test',
+          repository='https://chromium.googlesource.com/chromiumos/tryjobs.git',
+          revision=api.gitiles.make_hash('test'),
+          cbb_config='binhost-pre-cq',
+          cbb_extra_args='["--timeout", "14400", "--remote-trybot",'
+                         '"--remote-version=4"]',
+          buildbucket=json.dumps({'build': {'id':'12345'}})

[dnj (Google), 2016/07/20 01:37:06]

(api.json.dumps....)

[nxia1, 2016/07/20 05:24:22]

api.json in GenTests uses
https://github.com/luci/recipes-py/blob/master/recipe_modules/json/test_api.py
which doesn't provide the dumps method. 

should add a dumps() method in json/test_api.py first?

[dnj (Google), 2016/07/20 06:00:40]

Ugh well that's dumb. Looks like other recipes have also had to import "json"
for test, so let's just go with that.

+      )
+      + api.chromite.seed_chromite_config(_CHROMITE_CONFIG)
+  )