Make linux_chromium_headless_rel non-experimental in the CQ.

infra/config/cq.cfg

Index: infra/config/cq.cfg
diff --git a/infra/config/cq.cfg b/infra/config/cq.cfg
index d567ae6e1571b0facee15a00edfc5966c203c295..2412a3e5c8a627f86c47e895aa457078829be423 100644
--- a/infra/config/cq.cfg
+++ b/infra/config/cq.cfg
@@ -75,10 +75,7 @@ verifiers {
       # TODO(dpranke): reenable ASAP; see crbug.com/669297.
       #builders { name: "linux_chromium_clobber_rel_ng" }
       builders { name: "linux_chromium_compile_dbg_ng" }
-      builders {
-        name: "linux_chromium_headless_rel"
-        experiment_percentage: 100
-      }
+      builders { name: "linux_chromium_headless_rel" }
       builders { name: "linux_chromium_rel_ng" }
       builders { name: "linux_chromium_tsan_rel_ng" }
     }