Land Recent QUIC changes.

net/quic/crypto/aes_128_gcm_12_encrypter_nss.cc

Index: net/quic/crypto/aes_128_gcm_12_encrypter_nss.cc
diff --git a/net/quic/crypto/aes_128_gcm_12_encrypter_nss.cc b/net/quic/crypto/aes_128_gcm_12_encrypter_nss.cc
index 4729ef81bffce311a52a57c0308165e7170f2509..1cd3540c8844b4b66d897af4bd5932ee144ed1ed 100644
--- a/net/quic/crypto/aes_128_gcm_12_encrypter_nss.cc
+++ b/net/quic/crypto/aes_128_gcm_12_encrypter_nss.cc
@@ -250,7 +250,7 @@ SECStatus My_Encrypt(PK11SymKey* key,
 
 }  // namespace
 
-Aes128Gcm12Encrypter::Aes128Gcm12Encrypter() {
+Aes128Gcm12Encrypter::Aes128Gcm12Encrypter() : last_seq_num_(0) {
   ignore_result(g_gcm_support_checker.Get());
 }
 
@@ -350,6 +350,12 @@ QuicData* Aes128Gcm12Encrypter::EncryptPacket(
   size_t ciphertext_size = GetCiphertextSize(plaintext.length());
   scoped_ptr<char[]> ciphertext(new char[ciphertext_size]);
 
+  if (last_seq_num_ != 0 && sequence_number <= last_seq_num_) {
+    DLOG(FATAL) << "Sequence numbers regressed";
+    return NULL;
+  }
+  last_seq_num_ = sequence_number;
+
   uint8 nonce[kNoncePrefixSize + sizeof(sequence_number)];
   COMPILE_ASSERT(sizeof(nonce) == kAESNonceSize, bad_sequence_number_size);
   memcpy(nonce, nonce_prefix_, kNoncePrefixSize);