Introduce QUIC_VERSION_20: allowing endpoints to set different

net/quic/crypto/crypto_protocol.h

Index: net/quic/crypto/crypto_protocol.h
diff --git a/net/quic/crypto/crypto_protocol.h b/net/quic/crypto/crypto_protocol.h
index d1931d1a06e388b2d2fcd3e24a5f3f1e4b9c8d82..f2e7a16399f0a35ce833ae7de7a1fe46110d9ce1 100644
--- a/net/quic/crypto/crypto_protocol.h
+++ b/net/quic/crypto/crypto_protocol.h
@@ -91,11 +91,15 @@ const QuicTag kPROF = TAG('P', 'R', 'O', 'F');   // Proof (signature).
 const QuicTag kCCS  = TAG('C', 'C', 'S', 0);     // Common certificate set
 const QuicTag kCCRT = TAG('C', 'C', 'R', 'T');   // Cached certificate
 const QuicTag kEXPY = TAG('E', 'X', 'P', 'Y');   // Expiry
+// TODO(rjshade): Remove kIFCW when removing QUIC_VERSION_19.
 const QuicTag kIFCW = TAG('I', 'F', 'C', 'W');   // Initial flow control receive
                                                  // window.
+const QuicTag kSFCW = TAG('S', 'F', 'C', 'W');   // Initial stream flow control
+                                                 // receive window.
+const QuicTag kCFCW = TAG('C', 'F', 'C', 'W');   // Initial session/connection
+                                                 // flow control receive window.
 const QuicTag kUAID = TAG('U', 'A', 'I', 'D');   // Client's User Agent ID.
 
-
 // Server hello tags
 const QuicTag kCADR = TAG('C', 'A', 'D', 'R');   // Client IP address and port