Expose ProofSource::Details on QuicCryptoServerStream

Move ProofSource::Details caching from GfeQuicCryptoServerStream to parent class, not flag protected

PiperOrigin-RevId: 325537643
Change-Id: Idc71b12e1b7a2945e170c972e12a45707ec82457
diff --git a/quic/core/quic_crypto_server_stream_base.h b/quic/core/quic_crypto_server_stream_base.h
index 540b7a4..bea998d 100644
--- a/quic/core/quic_crypto_server_stream_base.h
+++ b/quic/core/quic_crypto_server_stream_base.h
@@ -84,6 +84,12 @@
   // However, it is exposed here because that is the only place where the
   // configuration for the certificate used in the connection is accessible.
   virtual bool ShouldSendExpectCTHeader() const = 0;
+
+  // Returns the Details from the latest call to ProofSource::GetProof or
+  // ProofSource::ComputeTlsSignature. Returns nullptr if no such call has been
+  // made. The Details are owned by the QuicCryptoServerStreamBase and the
+  // pointer is only valid while the owning object is still valid.
+  virtual const ProofSource::Details* ProofSourceDetails() const = 0;
 };
 
 // Creates an appropriate QuicCryptoServerStream for the provided parameters,