Adds definitions for soft AP metrics in wifi.proto

Adds definitions for soft AP metrics related to number of connected
clients and soft AP sessions

Bug: 68712260
Test: None
Change-Id: I515afd215a04fd50b0045fa1d81eebb9354f7bb2

proto/src/wifi.proto

@@ -364,6 +364,12 @@ message WifiLog {
   // (one value added per unique ESS - potentially multiple counts per single
   // scan!)
   repeated NumConnectableNetworksBucket observed_hotspot_r2_aps_per_ess_in_scan_histogram = 88;
+
+  // SoftAP event list tracking sessions and client counts in tethered mode
+  repeated SoftApConnectedClientsEvent soft_ap_connected_clients_events_tethered = 89;
+
+  // SoftAP event list tracking sessions and client counts in local only mode
+  repeated SoftApConnectedClientsEvent soft_ap_connected_clients_events_local_only = 90;
 }
 
 // Information that gets logged for every WiFi connection.
@@ -1071,3 +1077,29 @@ message ConnectToNetworkNotificationAndActionCount {
   // Occurrences of this action.
   optional int32 count = 4;
 }
+
+// SoftAP event tracking sessions and client counts
+message SoftApConnectedClientsEvent {
+
+  // Soft AP event Types
+  enum SoftApEventType {
+
+    // Soft AP is Up and ready for use
+    SOFT_AP_UP = 0;
+
+    // Soft AP is Down
+    SOFT_AP_DOWN = 1;
+
+    // Number of connected soft AP clients has changed
+    NUM_CLIENTS_CHANGED = 2;
+  }
+
+  // Type of event being recorded
+  optional SoftApEventType event_type = 1;
+
+  // Absolute time when event happened
+  optional int64 time_stamp_millis = 2;
+
+  // Number of connected clients if event_type is NUM_CLIENTS_CHANGED, otherwise zero.
+  optional int32 num_connected_clients = 3;
+}