Rename quic::kMaxPacketSize to quic::kMaxOutgoingPacketSize

As part of cl/242197597, QUIC now has separate values for maximum incoming and outgoing packet sizes. This CL renames the constant to be clearer.

gfe-relnote: constant rename, no functional impact
PiperOrigin-RevId: 242708648
Change-Id: I3f440ba44b9c12394026116aaecdd2c166cc63b6
diff --git a/quic/core/quic_connection.cc b/quic/core/quic_connection.cc
index 822b269..d90413a 100644
--- a/quic/core/quic_connection.cc
+++ b/quic/core/quic_connection.cc
@@ -2251,8 +2251,9 @@
       packet_generator_.FlushAllQueuedFrames();
     }
     DCHECK(!packet_generator_.HasQueuedFrames());
-    char buffer[kMaxPacketSize];
-    packet_generator_.ReserializeAllFrames(pending, buffer, kMaxPacketSize);
+    char buffer[kMaxOutgoingPacketSize];
+    packet_generator_.ReserializeAllFrames(pending, buffer,
+                                           kMaxOutgoingPacketSize);
   }
 }
 
@@ -2420,7 +2421,7 @@
     }
   }
 
-  DCHECK_LE(encrypted_length, kMaxPacketSize);
+  DCHECK_LE(encrypted_length, kMaxOutgoingPacketSize);
   DCHECK_LE(encrypted_length, packet_generator_.GetCurrentMaxPacketLength());
   QUIC_DVLOG(1) << ENDPOINT << "Sending packet " << packet_number << " : "
                 << (IsRetransmittable(*packet) == HAS_RETRANSMITTABLE_DATA
@@ -3427,8 +3428,8 @@
   if (max_packet_size > writer_limit) {
     max_packet_size = writer_limit;
   }
-  if (max_packet_size > kMaxPacketSize) {
-    max_packet_size = kMaxPacketSize;
+  if (max_packet_size > kMaxOutgoingPacketSize) {
+    max_packet_size = kMaxOutgoingPacketSize;
   }
   return max_packet_size;
 }