SPDY: Add WriteHeaders interface to SpdySession and SpdyStream

net/spdy/spdy_stream.cc

Index: net/spdy/spdy_stream.cc
diff --git a/net/spdy/spdy_stream.cc b/net/spdy/spdy_stream.cc
index 4fe34362cad5ffb2250a942f1aa219a002419aec..5ccc7727f726f567285c252bc68e55addaf8a9f8 100644
--- a/net/spdy/spdy_stream.cc
+++ b/net/spdy/spdy_stream.cc
@@ -479,6 +479,14 @@ int SpdyStream::SendRequest(bool has_upload_data) {
   return DoLoop(OK);
 }
 
+int SpdyStream::WriteHeaders(const SpdyHeaderBlock& headers,
+                             SpdyControlFlags flags) {
+  // Until the first headers by SYN_STREAM have been completely sent, we can
+  // not be sure that our stream_id is correct.
+  DCHECK_GT(io_state_, STATE_SEND_HEADERS_COMPLETE);
+  return session_->WriteHeaders(stream_id_, headers, flags);
+}
+
 int SpdyStream::WriteStreamData(IOBuffer* data, int length,
                                 SpdyDataFlags flags) {
   // Until the headers have been completely sent, we can not be sure