buildbucket: use acl sets

cr-buildbucket.cfg

Index: cr-buildbucket.cfg
diff --git a/cr-buildbucket.cfg b/cr-buildbucket.cfg
index 123c4374c0d24a2c52ed6afb610066d7bd9e9b48..bb44c7017e6453ac51e435d562b70d1c717a315e 100644
--- a/cr-buildbucket.cfg
+++ b/cr-buildbucket.cfg
@@ -6,12 +6,14 @@
 #
 # Please keep this list sorted by bucket name.
 
-buckets {
-  name: "master.chromium.webrtc"
+acl_sets {
+  name: "default"
   acls {
     role: READER
     group: "all"
   }
+
+  # Remove this rule after all Buildbot masters are turned down.
   acls {
     role: WRITER
     group: "service-account-webrtc-master"
@@ -19,56 +21,33 @@ buckets {
 }
 
 buckets {
+  name: "master.chromium.webrtc"
+  acl_sets: "default"
+}
+
+buckets {
   name: "master.chromium.webrtc.fyi"
-  acls {
-    role: READER
-    group: "all"
-  }
-  acls {
-    role: WRITER
-    group: "service-account-webrtc-master"
-  }
+  acl_sets: "default"
 }
 
 buckets {
   name: "master.client.webrtc"
-  acls {
-    role: READER
-    group: "all"
-  }
-  acls {
-    role: WRITER
-    group: "service-account-webrtc-master"
-  }
+  acl_sets: "default"
 }
 
 buckets {
   name: "master.client.webrtc.fyi"
-  acls {
-    role: READER
-    group: "all"
-  }
-  acls {
-    role: WRITER
-    group: "service-account-webrtc-master"
-  }
+  acl_sets: "default"
 }
 
 buckets {
   name: "master.tryserver.webrtc"
-  acls {
-    role: READER
-    group: "all"
-  }
+  acl_sets: "default"
   acls {
     role: SCHEDULER
     group: "service-account-cq"
   }
   acls {
-    role: WRITER
-    group: "service-account-webrtc-master"
-  }
-  acls {
     role: SCHEDULER
     group: "project-webrtc-tryjob-access"
   }