cr-buildbucket-dev: add findit mixin

cr-buildbucket-dev.cfg

Index: cr-buildbucket-dev.cfg
diff --git a/cr-buildbucket-dev.cfg b/cr-buildbucket-dev.cfg
index e6428aaf339a9e21e786f428711f3644d5983269..901a5e3bf48570a662f7536a3a2074b4e6652e94 100644
--- a/cr-buildbucket-dev.cfg
+++ b/cr-buildbucket-dev.cfg
@@ -57,6 +57,15 @@ builder_mixins {
   dimensions: "os:Windows"
 }
 
+builder_mixins {
+  name: "findit"
+  # This category is meant for Findit to trigger tryjobs on.
+  category: "Chromium Variable"
+  recipe {
+    name: "findit/chromium/compile"
+  }
+}
+
 buckets {
   name: "luci.chromium.try"