Improve QuicCryptoServerStreamBase functions for querying resumption status

QuicCryptoServerStreamBase::ZeroRttAttempted is currently only used in one
place, which is to query whether or not the client attempted to resume the
crypto connection. In QUIC Crypto, the only way to resume a connection is if
it's a 0-RTT connection, but in TLS, a resumption can occur without 0-RTT.
Given this difference, it makes sense to change the semantics (and name) of
ZeroRttAttempted to match its use (and simplify its implementation for the
TLS handshake). This CL also implements the previously unimplemented
TlsServerHandshaker::ResumptionAttempted.

QuicCryptoServerStreamBase is also missing a function to query whether the
connection was actually a resumption, so this CL adds the unused
IsResumption function.

No behavior changes: renames a method, adds new unused method, not flag protected

PiperOrigin-RevId: 314368205
Change-Id: I985fbc278493f6f104db9b509d83103e37bca48f
diff --git a/quic/core/quic_crypto_server_stream.cc b/quic/core/quic_crypto_server_stream.cc
index 66f8229..c7dd2d9 100644
--- a/quic/core/quic_crypto_server_stream.cc
+++ b/quic/core/quic_crypto_server_stream.cc
@@ -298,6 +298,11 @@
          num_handshake_messages_with_server_nonces_ == 0;
 }
 
+bool QuicCryptoServerStream::IsResumption() const {
+  // QUIC Crypto doesn't have a non-0-RTT resumption mode.
+  return IsZeroRtt();
+}
+
 int QuicCryptoServerStream::NumServerConfigUpdateMessagesSent() const {
   return num_server_config_update_messages_sent_;
 }
@@ -307,7 +312,7 @@
   return previous_cached_network_params_.get();
 }
 
-bool QuicCryptoServerStream::ZeroRttAttempted() const {
+bool QuicCryptoServerStream::ResumptionAttempted() const {
   return zero_rtt_attempted_;
 }