Send two QUIC alternate addresses from GFE for proxied sessions

Currently the GFE sends one address to proxied sessions, based on the address family that the client is currently using. This CL changes that to allow the GFE to send both IPv4 and IPv6 addresses to the client. The change is protected by gfe2_reloadable_flag_quic_send_two_alt_addresses.

This CL also removes deprecated QuicConfig APIs now that they are no longer used.

gfe-relnote: send 2 alternate addresses, protected by gfe2_reloadable_flag_quic_send_two_alt_addresses
PiperOrigin-RevId: 309798078
Change-Id: I4b5c55f532aceacc41a807c8f6d810311ee236dc

quic/core/quic_config.cc

diff --git a/quic/core/quic_config.cc b/quic/core/quic_config.cc
index 5cd0061..644c8f0 100644
--- a/quic/core/quic_config.cc
+++ b/quic/core/quic_config.cc
@@ -911,30 +911,6 @@
   return alternate_server_address_ipv4_.GetReceivedValue();
 }
 
-void QuicConfig::SetAlternateServerAddressToSend(
-    const QuicSocketAddress& alternate_server_address) {
-  if (alternate_server_address.host().IsIPv6()) {
-    SetIPv6AlternateServerAddressToSend(alternate_server_address);
-  } else if (alternate_server_address.host().IsIPv4()) {
-    SetIPv4AlternateServerAddressToSend(alternate_server_address);
-  } else {
-    QUIC_BUG << "Cannot use SetAlternateServerAddressToSend with "
-             << alternate_server_address;
-  }
-}
-
-bool QuicConfig::HasReceivedAlternateServerAddress() const {
-  return HasReceivedIPv6AlternateServerAddress() ||
-         HasReceivedIPv4AlternateServerAddress();
-}
-
-const QuicSocketAddress& QuicConfig::ReceivedAlternateServerAddress() const {
-  if (HasReceivedIPv6AlternateServerAddress()) {
-    return ReceivedIPv6AlternateServerAddress();
-  }
-  return ReceivedIPv4AlternateServerAddress();
-}
-
 void QuicConfig::SetStatelessResetTokenToSend(
     QuicUint128 stateless_reset_token) {
   stateless_reset_token_.SetSendValue(stateless_reset_token);

quic/core/quic_config.h

diff --git a/quic/core/quic_config.h b/quic/core/quic_config.h
index 4caba41..a46af4d 100644
--- a/quic/core/quic_config.h
+++ b/quic/core/quic_config.h
@@ -463,12 +463,6 @@
   bool HasReceivedIPv4AlternateServerAddress() const;
   const QuicSocketAddress& ReceivedIPv4AlternateServerAddress() const;
 
-  // DEPRECATED: use the variants that specify the address family (IPv4/IPv6).
-  void SetAlternateServerAddressToSend(
-      const QuicSocketAddress& alternate_server_address);
-  bool HasReceivedAlternateServerAddress() const;
-  const QuicSocketAddress& ReceivedAlternateServerAddress() const;
-
   void SetStatelessResetTokenToSend(QuicUint128 stateless_reset_token);
 
   bool HasReceivedStatelessResetToken() const;