Support Face Virtual HAL operation latency randomization

Bug: 294254230
Test: atest android.hardware.biometrics.face.*
Change-Id: I1e0c2ba2f0f6756c79375b56c7d1a10f7f3bf5c4
diff --git a/biometrics/face/aidl/default/FakeFaceEngine.h b/biometrics/face/aidl/default/FakeFaceEngine.h
index 8d9303c..b1e1388 100644
--- a/biometrics/face/aidl/default/FakeFaceEngine.h
+++ b/biometrics/face/aidl/default/FakeFaceEngine.h
@@ -60,6 +60,7 @@
     void getAuthenticatorIdImpl(ISessionCallback* cb);
     void invalidateAuthenticatorIdImpl(ISessionCallback* cb);
     void resetLockoutImpl(ISessionCallback* cb, const keymaster::HardwareAuthToken& /*hat*/);
+    int32_t getLatency(const std::vector<std::optional<std::int32_t>>& latencyVec);
 
     virtual std::string toString() const {
         std::ostringstream os;
@@ -71,6 +72,7 @@
     std::mt19937 mRandom;
 
   private:
+    int32_t getRandomInRange(int32_t bound1, int32_t bound2);
     static constexpr int32_t FACE_ACQUIRED_VENDOR_BASE = 1000;
     static constexpr int32_t FACE_ERROR_VENDOR_BASE = 1000;
     std::pair<AcquiredInfo, int32_t> convertAcquiredInfo(int32_t code);