Add GetFastPairVersion to DeviceMetadata

PiperOrigin-RevId: 520094589

fastpair/repository/device_metadata.h

@@ -18,6 +18,7 @@
 #include <utility>
 
 #include "fastpair/proto/fastpair_rpcs.proto.h"
+#include "fastpair/common/fast_pair_device.h"
 
 namespace nearby {
 namespace fastpair {
@@ -35,6 +36,15 @@ class DeviceMetadata {
     return response_;
   }
 
+  DeviceFastPairVersion GetFastPairVersion() const {
+    // Anti-spoofing keys were introduced in Fast Pair v2, so if this isn't
+    // available then the device is v1.
+    if (GetDetails().anti_spoofing_key_pair().public_key().empty()) {
+      return DeviceFastPairVersion::kV1;
+    }
+    return DeviceFastPairVersion::kHigherThanV1;
+  }
+
  private:
   const proto::GetObservedDeviceResponse response_;
 };