In QUIC v39, read and write integers and floating numbers in big endian.

net/quic/core/quic_packet_creator.cc

Index: net/quic/core/quic_packet_creator.cc
diff --git a/net/quic/core/quic_packet_creator.cc b/net/quic/core/quic_packet_creator.cc
index e249fd858b77423c91994d520066fe1490eb3835..0d2e293f6125af787845b2528f8eb64b9c1806e6 100644
--- a/net/quic/core/quic_packet_creator.cc
+++ b/net/quic/core/quic_packet_creator.cc
@@ -367,7 +367,7 @@ void QuicPacketCreator::CreateAndSerializeStreamFrame(
   FillPacketHeader(&header);
   QUIC_CACHELINE_ALIGNED char encrypted_buffer[kMaxPacketSize];
   QuicDataWriter writer(arraysize(encrypted_buffer), encrypted_buffer,
-                        framer_->perspective(), HOST_BYTE_ORDER);
+                        framer_->perspective(), framer_->endianness());
   if (!framer_->AppendPacketHeader(header, &writer)) {
     QUIC_BUG << "AppendPacketHeader failed";
     return;