Various QUIC cleanups to sync with internal code.

net/quic/quic_framer.cc

Index: net/quic/quic_framer.cc
diff --git a/net/quic/quic_framer.cc b/net/quic/quic_framer.cc
index 3dd72b90d9340748f26f9e2e5a7a7e35143cc511..9d15c3c5130a5d2a18ab3424579adc8bb823b195 100644
--- a/net/quic/quic_framer.cc
+++ b/net/quic/quic_framer.cc
@@ -18,6 +18,8 @@ using std::min;
 using std::numeric_limits;
 using std::string;
 
+bool FLAGS_quic_allow_oversized_packets_for_test = false;
+
 namespace net {
 
 namespace {
@@ -266,6 +268,8 @@ size_t QuicFramer::GetSerializedFrameLength(
       // Note that we may not use every byte of the writer in this case.
       DVLOG(1) << "Truncating large frame";
       return free_bytes;
+    } else if (!FLAGS_quic_allow_oversized_packets_for_test) {
+      return 0;
     }
   }
   return frame_len;
@@ -1729,7 +1733,7 @@ bool QuicFramer::AppendPacketSequenceNumber(
           packet_sequence_number & k6ByteSequenceNumberMask);
       break;
     default:
-      NOTREACHED() << "sequence_number_length: " << sequence_number_length;
+      DCHECK(false) << "sequence_number_length: " << sequence_number_length;
       return false;
   }
 }