Change IETF Frame/QUIC_VERSION_99 tests to be symbolic.

This CL replaces checks for QUIC_VERSION_99 that are controlling the IETF frames and their associated functionality with a function call . The function has a name that is indicative of the features for which the version is being checked -- VersionHasIetfQuicFrames().

gfe-relnote: N/A just changes the text by which we test if IETF QUIC has been negotiated.
PiperOrigin-RevId: 253767805
Change-Id: I08ae6738411ac151f90d5d085ea69af90d79fb80

quic/core/quic_dispatcher.cc

diff --git a/quic/core/quic_dispatcher.cc b/quic/core/quic_dispatcher.cc
index 1025ed1..9b59aa5 100644
--- a/quic/core/quic_dispatcher.cc
+++ b/quic/core/quic_dispatcher.cc
@@ -134,7 +134,7 @@
                        bool ietf_quic) {
     QuicConnectionCloseFrame* frame =
         new QuicConnectionCloseFrame(error_code, error_details);
-    if (framer_.transport_version() == QUIC_VERSION_99) {
+    if (VersionHasIetfQuicFrames(framer_.transport_version())) {
       frame->close_type = IETF_QUIC_TRANSPORT_CONNECTION_CLOSE;
     }