metrics: add proto field for wifi radio usage

Bug: 77603419
Test: compile, unit tests
Change-Id: I13cc950462800acb33c9e7b40958ec2fe002e946

proto/src/wifi.proto

@@ -457,6 +457,8 @@ message WifiLog {
   // Identifier for experimental scoring parameter settings.
   optional string score_experiment_id = 117;
 
+  // Data on wifi radio usage
+  optional WifiRadioUsage wifi_radio_usage = 118;
 }
 
 // Information that gets logged for every WiFi connection.
@@ -1503,3 +1505,12 @@ message WifiRttLog {
     optional int32 count = 2;
   }
 }
+
+// Usage data for the wifi radio while device is running on battery.
+message WifiRadioUsage {
+  // Duration of log (ms)
+  optional int64 logging_duration_ms = 1;
+
+  // Total time for which the radio is awake due to scan.
+  optional int64 scan_time_ms = 2;
+}