Give the auto-merger somthing to hang on to.

Bug: 29001173
Change-Id: Ie244f79f1569e2b32be4046d111919120ce6111e
diff --git a/proto/src/metrics_constants.proto b/proto/src/metrics_constants.proto
index 3a14ad2..1dcb13c 100644
--- a/proto/src/metrics_constants.proto
+++ b/proto/src/metrics_constants.proto
@@ -2256,6 +2256,8 @@
     // CATEGORY: SETTINGS
     SETTINGS_GESTURES = 459;
 
+    // ---- End N-MR1 Constants, all N-MR1 constants go above this line ----
+
     // Add new aosp constants above this line.
     // END OF AOSP CONSTANTS
   }