Add histograms to track stalled spdy streams.

net/spdy/spdy_session.h

 // Copyright (c) 2010 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.
 
 #ifndef NET_SPDY_SPDY_SESSION_H_
 #define NET_SPDY_SPDY_SESSION_H_
 #pragma once
 
 #include <deque>
 #include <list>
@@ skipping 393 matching lines @@
 
   // Some statistics counters for the session.
   int streams_initiated_count_;
   int streams_pushed_count_;
   int streams_pushed_and_claimed_count_;
   int streams_abandoned_count_;
   int frames_received_;
   bool sent_settings_;      // Did this session send settings when it started.
   bool received_settings_;  // Did this session receive at least one settings
                             // frame.
+  int stalled_streams_;     // Count of streams that were ever stalled.
 
   // Initial send window size for the session; can be changed by an
   // arriving SETTINGS frame; newly created streams use this value for the
   // initial send window size.
   int initial_send_window_size_;
 
   // Initial receive window size for the session; there are plans to add a
   // command line switch that would cause a SETTINGS frame with window size
   // announcement to be sent on startup; newly created streams will use
   // this value for the initial receive window size.
@@ skipping 26 matching lines @@
   const spdy::SpdyControlFlags flags_;
   const spdy::SpdyStreamId id_;
   const spdy::SpdyStreamId associated_stream_;
 
   DISALLOW_COPY_AND_ASSIGN(NetLogSpdySynParameter);
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_SPDY_SESSION_H_