Add a new SpdyStream::Delegate method to handle trailers

net/spdy/spdy_proxy_client_socket.cc

Index: net/spdy/spdy_proxy_client_socket.cc
diff --git a/net/spdy/spdy_proxy_client_socket.cc b/net/spdy/spdy_proxy_client_socket.cc
index 39fbd60cf33d0e7e0a77d7c7f1fc87508ec1d85e..64b54a412282f6ff553e541aa7a90f8d93d7e7b9 100644
--- a/net/spdy/spdy_proxy_client_socket.cc
+++ b/net/spdy/spdy_proxy_client_socket.cc
@@ -496,6 +496,8 @@ void SpdyProxyClientSocket::OnDataSent()  {
                             ResetAndReturn(&write_callback_), rv));
 }
 
+void SpdyProxyClientSocket::OnTrailers(const SpdyHeaderBlock& trailers) {}

[Ryan Hamilton, 2015/08/10 22:37:38]

Ignoring headers is fine, though you could also close the connection with some
sort of error, if you wish. I can't imagine trailers make any sense for a
CONNECT tunnel.

[xunjieli, 2015/08/11 15:07:14]

I added a comment. I am not sure how to close the connection with an error.
There's a Disconnect() method, but it only resets the stream with
STATUS_CODE_CANCEL. Should we do that here? 

[Ryan Hamilton, 2015/08/11 16:30:09]

Hm. Good question :> Perhaps leaving it alone is fine. Now that I think about
it, I don't that the proxy client socket's SpdyStream is a
REQUEST_RESPONSE_STREAM, so perhaps you can just put NOTREACHED() here, but
OnTrailers() will never be called?

[xunjieli, 2015/08/11 17:58:11]

Done. You are right -- the proxy client socket's SpdyStream is of type
SPDY_BIDIRECTIONAL_STREAM, so trailers will be combined with response headers.
NOTREACHED here makes sense.

+
 void SpdyProxyClientSocket::OnClose(int status)  {
   was_ever_used_ = spdy_stream_->WasEverUsed();
   spdy_stream_.reset();