Re-land: Defer SpdySession destruction to support closing writes

net/spdy/spdy_proxy_client_socket.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_proxy_client_socket.h"
 
 #include <algorithm>  // min
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 392 matching lines @@
     case 200:  // OK
       next_state_ = STATE_OPEN;
       return OK;
 
     case 302:  // Found / Moved Temporarily
       // Try to return a sanitized response so we can follow auth redirects.
       // If we can't, fail the tunnel connection.
       if (SanitizeProxyRedirect(&response_, request_.url)) {
         redirect_has_load_timing_info_ =
             spdy_stream_->GetLoadTimingInfo(&redirect_load_timing_info_);
+        // Note that this triggers a RST_STREAM_CANCEL.
         spdy_stream_->DetachDelegate();
         next_state_ = STATE_DISCONNECTED;
         return ERR_HTTPS_PROXY_TUNNEL_RESPONSE;
       } else {
         LogBlockedTunnelResponse();
         return ERR_TUNNEL_CONNECTION_FAILED;
       }
 
     case 407:  // Proxy Authentication Required
       next_state_ = STATE_OPEN;
@@ skipping 93 matching lines @@
   } else if (!read_callback_.is_null()) {
     // If we have a read_callback_, the we need to make sure we call it back.
     OnDataReceived(scoped_ptr<SpdyBuffer>());
   }
   // This may have been deleted by read_callback_, so check first.
   if (weak_ptr.get() && !write_callback.is_null())
     write_callback.Run(ERR_CONNECTION_CLOSED);
 }
 
 }  // namespace net