Stop using SpdySynReplyIR for SPDY 4.

net/spdy/spdy_framer.cc

Index: net/spdy/spdy_framer.cc
diff --git a/net/spdy/spdy_framer.cc b/net/spdy/spdy_framer.cc
index 77aa413a78cf14013d50387e7e2b268c73ef31f2..88a05ea85967912be077675e8602ea1928f61b19 100644
--- a/net/spdy/spdy_framer.cc
+++ b/net/spdy/spdy_framer.cc
@@ -2416,32 +2416,15 @@ SpdySerializedFrame* SpdyFramer::SerializeSynStream(
 
 SpdySerializedFrame* SpdyFramer::SerializeSynReply(
     const SpdySynReplyIR& syn_reply) {
+  DCHECK_GE(SPDY3, protocol_version());
   uint8 flags = 0;
   if (syn_reply.fin()) {
     flags |= CONTROL_FLAG_FIN;
   }
-  // In SPDY >= 4, SYN_REPLY frames are HEADERS frames, but for now
-  // we never expect to have to overflow into a CONTINUATION frame.
-  if (protocol_version() > SPDY3) {
-    flags |= HEADERS_FLAG_END_HEADERS;
-  }
 
   // The size of this frame, including variable-length name-value block.
-  size_t size = GetSynReplyMinimumSize();
-
-  string hpack_encoding;
-  if (protocol_version() > SPDY3) {
-    if (enable_compression_) {
-      GetHpackEncoder()->EncodeHeaderSet(
-          syn_reply.name_value_block(), &hpack_encoding);
-    } else {
-      GetHpackEncoder()->EncodeHeaderSetWithoutCompression(
-          syn_reply.name_value_block(), &hpack_encoding);
-    }
-    size += hpack_encoding.size();
-  } else {
-    size += GetSerializedLength(syn_reply.name_value_block());
-  }
+  const size_t size = GetSynReplyMinimumSize() +
+                      GetSerializedLength(syn_reply.name_value_block());
 
   SpdyFrameBuilder builder(size, protocol_version());
   if (protocol_version() <= SPDY3) {
@@ -2457,17 +2440,11 @@ SpdySerializedFrame* SpdyFramer::SerializeSynReply(
     builder.WriteUInt16(0);  // Unused.
   }
   DCHECK_EQ(GetSynReplyMinimumSize(), builder.length());
-  if (protocol_version() > SPDY3) {
-    builder.WriteBytes(&hpack_encoding[0], hpack_encoding.size());
-  } else {
-    SerializeNameValueBlock(&builder, syn_reply);
-  }
+  SerializeNameValueBlock(&builder, syn_reply);
 
   if (debug_visitor_) {
-    const size_t payload_len = protocol_version() > SPDY3 ?
-        hpack_encoding.size() :
-        GetSerializedLength(protocol_version(),
-                            &(syn_reply.name_value_block()));
+    const size_t payload_len = GetSerializedLength(
+        protocol_version(), &(syn_reply.name_value_block()));
     debug_visitor_->OnSendCompressedFrame(syn_reply.stream_id(),
                                           SYN_REPLY,
                                           payload_len,