Add code counts for legacy MESSAGE frame codepoints.

PiperOrigin-RevId: 597909461

quiche/quic/core/quic_framer.cc

diff --git a/quiche/quic/core/quic_framer.cc b/quiche/quic/core/quic_framer.cc
index b967645..8f3a736 100644
--- a/quiche/quic/core/quic_framer.cc
+++ b/quiche/quic/core/quic_framer.cc
@@ -2669,6 +2669,7 @@
       case IETF_EXTENSION_MESSAGE_NO_LENGTH:
         ABSL_FALLTHROUGH_INTENDED;
       case IETF_EXTENSION_MESSAGE: {
+        QUIC_CODE_COUNT(quic_legacy_message_frame_codepoint_read);
         QuicMessageFrame message_frame;
         if (!ProcessMessageFrame(reader,
                                  frame_type == IETF_EXTENSION_MESSAGE_NO_LENGTH,
@@ -5805,6 +5806,7 @@
     type_byte = last_frame_in_packet ? IETF_EXTENSION_MESSAGE_NO_LENGTH_V99
                                      : IETF_EXTENSION_MESSAGE_V99;
   } else {
+    QUIC_CODE_COUNT(quic_legacy_message_frame_codepoint_write);
     type_byte = last_frame_in_packet ? IETF_EXTENSION_MESSAGE_NO_LENGTH
                                      : IETF_EXTENSION_MESSAGE;
   }