Add metrics constants for the assist gesture.

Bug: 38508651
Test: make -j
Change-Id: I5ee7f20add9fedaec6928a81bce828a75816da99
diff --git a/proto/src/metrics_constants.proto b/proto/src/metrics_constants.proto
index edef16d..d8d91af 100644
--- a/proto/src/metrics_constants.proto
+++ b/proto/src/metrics_constants.proto
@@ -4005,6 +4005,26 @@
     // FIELD: The numeric preference value (of type float) when it is changed in Settings
     FIELD_SETTINGS_PREFERENCE_CHANGE_FLOAT_VALUE = 995;
 
+    // OPEN: Settings > System > Languages & input > Assist gesture
+    // CATEGORY: SETTINGS
+    // OS: O DR
+    SETTINGS_ASSIST_GESTURE = 996;
+
+    // ACTION: Assist gesture released without triggering
+    // CATEGORY: GLOBAL_SYSTEM_UI
+    // OS: O DR
+    ASSIST_GESTURE_RELEASED = 997;
+
+    // ACTION: Assist gesture primed
+    // CATEGORY: GLOBAL_SYSTEM_UI
+    // OS: O DR
+    ASSIST_GESTURE_PRIMED = 998;
+
+    // ACTION: Assist gesture triggered
+    // CATEGORY: GLOBAL_SYSTEM_UI
+    // OS: O DR
+    ASSIST_GESTURE_TRIGGERED = 999;
+
     // Add new aosp constants above this line.
     // END OF AOSP CONSTANTS
   }