Convert CryptoFramer::ConstructHandshakeMessage to return unique_ptr

gfe-relnote: Use unique_ptr for memory management rather than bare pointer. No functional change intended, not flag-protected.
PiperOrigin-RevId: 238454581
Change-Id: I2f0875854d8bc1983c2e5197abab7741d1985028
diff --git a/quic/core/quic_crypto_stream_test.cc b/quic/core/quic_crypto_stream_test.cc
index 2280434..ffadea6 100644
--- a/quic/core/quic_crypto_stream_test.cc
+++ b/quic/core/quic_crypto_stream_test.cc
@@ -80,7 +80,7 @@
 
   void ConstructHandshakeMessage() {
     CryptoFramer framer;
-    message_data_.reset(framer.ConstructHandshakeMessage(message_));
+    message_data_ = framer.ConstructHandshakeMessage(message_);
   }
 
  protected: