[nearby] Add discoveryTimestamp field

Test: -m
Bug: 306043245
Ignore-AOSP-First: nearby_not_in_aosp_yet
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:730894831d541ef67063e1d85e3b770476053fe6)
Merged-In: I2151cdeceec1a3180c79b0ea10adb6e5581f4845
Change-Id: I2151cdeceec1a3180c79b0ea10adb6e5581f4845

nearby/service/java/com/android/server/nearby/provider/ChreDiscoveryProvider.java

@@ -350,7 +350,10 @@ public class ChreDiscoveryProvider extends AbstractDiscoveryProvider {
                                             DataElement.DataType.ACTION,
                                             new byte[]{(byte) filterResult.getIntent()}));
                         }
-
+                        if (filterResult.hasDiscoveryTimestamp()) {
+                            presenceDeviceBuilder.setDiscoveryTimestampMillis(
+                                    filterResult.getDiscoveryTimestamp());
+                        }
                         PublicCredential publicCredential =
                                 new PublicCredential.Builder(
                                         secretId,

nearby/service/proto/src/presence/blefilter.proto

@@ -115,6 +115,7 @@ message BleFilterResult {
   repeated DataElement data_element = 7;
   optional bytes ble_service_data = 8;
   optional ResultType result_type = 9;
+  optional uint64 discovery_timestamp = 10; // Timestamp when the device is discovered.
 }
 
 message BleFilterResults {

nearby/tests/unit/src/com/android/server/nearby/provider/ChreDiscoveryProviderTest.java

@@ -262,6 +262,7 @@ public class ChreDiscoveryProviderTest {
                                 .setValue(ByteString.copyFrom(testData))
                                 .setValueLength(testData.length)
                         )
+                        .setDiscoveryTimestamp(1697765417070L)
                         .build();
         Blefilter.BleFilterResults results =
                 Blefilter.BleFilterResults.newBuilder().addResult(result).build();