Break out of the loop in QuicSession::OnCanWrite if the QuicConnection

net/quic/quic_connection.h

 // 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.
 //
 // The entity that handles framing writes for a Quic client or server.
 // Each QuicSession will have a connection associated with it.
 //
 // On the server side, the Dispatcher handles the raw reads, and hands off
 // packets via ProcessUdpPacket for framing and processing.
 //
@@ skipping 323 matching lines @@
   size_t NumQueuedPackets() const { return queued_packets_.size(); }
 
   QuicEncryptedPacket* ReleaseConnectionClosePacket() {
     return connection_close_packet_.release();
   }
 
   // Flush any queued frames immediately.  Preserves the batch write mode and
   // does nothing if there are no pending frames.
   void Flush();
 
+  // Returns true if the underlying UDP socket is writable, there is
+  // no queued data and the connection is not congestion-control
+  // blocked.
+  bool CanWriteStreamData();
+
   // Returns true if the connection has queued packets or frames.
   bool HasQueuedData() const;
 
   // Sets (or resets) the idle state connection timeout. Also, checks and times
   // out the connection if network timer has expired for |timeout|.
   void SetIdleNetworkTimeout(QuicTime::Delta timeout);
   // Sets (or resets) the total time delta the connection can be alive for.
   // Also, checks and times out the connection if timer has expired for
   // |timeout|. Used to limit the time a connection can be alive before crypto
   // handshake finishes.
@@ skipping 359 matching lines @@
   // If non-empty this contains the set of versions received in a
   // version negotiation packet.
   QuicVersionVector server_supported_versions_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicConnection);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_CONNECTION_H_