Replace QuicheOptional with absl::optional.

PiperOrigin-RevId: 336947387
Change-Id: I20fa90b62347b2fbb08e68db34a22cd182ef2b64
diff --git a/quic/qbone/qbone_stream_test.cc b/quic/qbone/qbone_stream_test.cc
index 702b2a4..c2b28ca 100644
--- a/quic/qbone/qbone_stream_test.cc
+++ b/quic/qbone/qbone_stream_test.cc
@@ -40,13 +40,12 @@
   ~MockQuicSession() override {}
 
   // Writes outgoing data from QuicStream to a string.
-  QuicConsumedData WritevData(
-      QuicStreamId id,
-      size_t write_length,
-      QuicStreamOffset offset,
-      StreamSendingState state,
-      TransmissionType type,
-      quiche::QuicheOptional<EncryptionLevel> level) override {
+  QuicConsumedData WritevData(QuicStreamId id,
+                              size_t write_length,
+                              QuicStreamOffset offset,
+                              StreamSendingState state,
+                              TransmissionType type,
+                              absl::optional<EncryptionLevel> level) override {
     if (!writable_) {
       return QuicConsumedData(0, false);
     }