Allow SPDY POSTs to be terminated by an empty FIN data frame.

net/spdy/spdy_session.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/spdy/spdy_session.h"
 
 #include <algorithm>
 #include <map>
 
 #include "base/basictypes.h"
@@ skipping 1164 matching lines @@
 
   // TODO(mbelshe): reduce memory copies here.
   DCHECK(buffered_spdy_framer_.get());
   scoped_ptr<SpdyFrame> frame(
       buffered_spdy_framer_->CreateDataFrame(
           stream_id, data->data(),
           static_cast<uint32>(effective_len), flags));
 
   scoped_ptr<SpdyBuffer> data_buffer(new SpdyBuffer(frame.Pass()));
 
-  if (flow_control_state_ == FLOW_CONTROL_STREAM_AND_SESSION) {
+  // Send window size is based on payload size, so nothing to do if this is
+  // just a FIN with no payload.
+  if (flow_control_state_ == FLOW_CONTROL_STREAM_AND_SESSION &&
+      effective_len != 0) {
     DecreaseSendWindowSize(static_cast<int32>(effective_len));
     data_buffer->AddConsumeCallback(
         base::Bind(&SpdySession::OnWriteBufferConsumed,
                    weak_factory_.GetWeakPtr(),
                    static_cast<size_t>(effective_len)));
   }
 
   return data_buffer.Pass();
 }
 
@@ skipping 1999 matching lines @@
     if (!queue->empty()) {
       SpdyStreamId stream_id = queue->front();
       queue->pop_front();
       return stream_id;
     }
   }
   return 0;
 }
 
 }  // namespace net