[RTT] Ranging timestamp is in millis

API review mods: change ranging timestamp to milliseconds. Update
docs to clarify which time is being measured.

Bug: 73088768
Test: unit tests & integration tests
Change-Id: I8a81e92d1a3d264abd98a1695be6a5da6fa5f6a1

api/current.txt

@@ -28524,7 +28524,7 @@ package android.net.wifi.rtt {
     method public int getDistanceStdDevMm();
     method public android.net.MacAddress getMacAddress();
     method public android.net.wifi.aware.PeerHandle getPeerHandle();
-    method public long getRangingTimestampUs();
+    method public long getRangingTimestampMillis();
     method public int getRssi();
     method public int getStatus();
     method public void writeToParcel(android.os.Parcel, int);

wifi/java/android/net/wifi/RttManager.java

@@ -992,7 +992,7 @@ public class RttManager {
                             legacyResults[i].distanceStandardDeviation =
                                     result.getDistanceStdDevMm() / 10;
                             legacyResults[i].rssi = result.getRssi() * -2;
-                            legacyResults[i].ts = result.getRangingTimestampUs();
+                            legacyResults[i].ts = result.getRangingTimestampMillis() * 1000;
                         } else {
                             // just in case legacy API needed some relatively real timestamp
                             legacyResults[i].ts = SystemClock.elapsedRealtime() * 1000;

wifi/java/android/net/wifi/rtt/RangingResult.java

@@ -228,15 +228,18 @@ public final class RangingResult implements Parcelable {
     }
 
     /**
-     * @return The timestamp, in us since boot, at which the ranging operation was performed.
+     * @return The timestamp at which the ranging operation was performed. The timestamp is in
+     * milliseconds since boot, including time spent in sleep, corresponding to values provided by
+     * {@link android.os.SystemClock#elapsedRealtime()}.
      * <p>
      * Only valid if {@link #getStatus()} returns {@link #STATUS_SUCCESS}, otherwise will throw an
      * exception.
      */
-    public long getRangingTimestampUs() {
+    public long getRangingTimestampMillis() {
         if (mStatus != STATUS_SUCCESS) {
             throw new IllegalStateException(
-                    "getRangingTimestamp(): invoked on an invalid result: getStatus()=" + mStatus);
+                    "getRangingTimestampMillis(): invoked on an invalid result: getStatus()="
+                            + mStatus);
         }
         return mTimestamp;
     }