Add a new SpdyStream::Delegate method to handle trailers

net/spdy/spdy_http_stream.cc

Index: net/spdy/spdy_http_stream.cc
diff --git a/net/spdy/spdy_http_stream.cc b/net/spdy/spdy_http_stream.cc
index f3da77bc803e419b8c7b0df76128d37652199234..fd708c8b97874c53ae28724541330482a285a03d 100644
--- a/net/spdy/spdy_http_stream.cc
+++ b/net/spdy/spdy_http_stream.cc
@@ -365,6 +365,9 @@ void SpdyHttpStream::OnDataSent() {
   ReadAndSendRequestBodyData();
 }
 
+// TODO(xunjieli): Maybe do something with the trailers. crbug.com/422958.
+void SpdyHttpStream::OnTrailers(const SpdyHeaderBlock& trailers) {}
+
 void SpdyHttpStream::OnClose(int status) {
   if (stream_.get()) {
     stream_closed_ = true;