Add Night display QSTile

Bug: 28615069
Bug: 29619615
Change-Id: Ie23bd1ed9266941682eceb5f2086201bf02af765
diff --git a/proto/src/metrics_constants.proto b/proto/src/metrics_constants.proto
index 966d0ec..ba59c2f 100644
--- a/proto/src/metrics_constants.proto
+++ b/proto/src/metrics_constants.proto
@@ -2188,6 +2188,12 @@
     // Settings launched from collapsed quick settings.
     ACTION_QS_COLLAPSED_SETTINGS_LAUNCH = 490;
 
+    // OPEN: QS Night mode tile shown
+    // ACTION: QS Night mode tile tapped
+    //   SUBTYPE: 0 is off, 1 is on
+    // CATEGORY: QUICK_SETTINGS
+    QS_NIGHT_DISPLAY = 491;
+
     // ---- End N-MR1 Constants, all N-MR1 constants go above this line ----
     // Add new aosp constants above this line.
     // END OF AOSP CONSTANTS