Add support for the control group in the Simple Cache Experiment.

net/disk_cache/experiments.h

Index: net/disk_cache/experiments.h
diff --git a/net/disk_cache/experiments.h b/net/disk_cache/experiments.h
index b088b08a23f0f38aae1f78c2e138e0794ca0353e..d7d4e58437b24d9185e157ea1d21572d576793db 100644
--- a/net/disk_cache/experiments.h
+++ b/net/disk_cache/experiments.h
@@ -17,7 +17,10 @@ enum {
   EXPERIMENT_DELETED_LIST_OUT = 11,
   EXPERIMENT_DELETED_LIST_CONTROL = 12,
   EXPERIMENT_DELETED_LIST_IN = 13,
-  EXPERIMENT_DELETED_LIST_OUT2 = 14
+  EXPERIMENT_DELETED_LIST_OUT2 = 14,
+  // There is no EXPERIMENT_SIMPLE_YES since this enum is used in the standard
+  // backend only.
+  EXPERIMENT_SIMPLE_CONTROL = 15,
 };
 
 }  // namespace disk_cache