Makes migration on write error asynchronous to avoid reentrancy issues

net/quic/chromium/quic_chromium_packet_writer.h

 // Copyright 2013 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_QUIC_QUIC_CHROMIUM_PACKET_WRITER_H_
 #define NET_QUIC_QUIC_CHROMIUM_PACKET_WRITER_H_
 
 #include <stddef.h>
 
 #include "base/macros.h"
@@ skipping 14 matching lines @@
   // Delegate interface which receives notifications on socket write events.
   class NET_EXPORT_PRIVATE Delegate {
    public:
     // Called when a socket write attempt results in a failure, so
     // that the delegate may recover from it by perhaps rewriting the
     // packet to a different socket. An implementation must return the
     // return value from the rewrite attempt if there is one, and
     // |error_code| otherwise.
     virtual int HandleWriteError(int error_code,
                                  scoped_refptr<StringIOBuffer> last_packet) = 0;
+
     // Called to propagate the final write error to the delegate.
     virtual void OnWriteError(int error_code) = 0;
+
     // Called when the writer is unblocked due to a write completion.
     virtual void OnWriteUnblocked() = 0;
+
+    // Called when the writer's IsWriteBlocked is called.
+    virtual bool ShouldWriteBlock() = 0;
   };
 
   QuicChromiumPacketWriter();
   // |socket| must outlive writer.
   explicit QuicChromiumPacketWriter(Socket* socket);
   ~QuicChromiumPacketWriter() override;
 
   // |delegate| must outlive writer.
   void set_delegate(Delegate* delegate) { delegate_ = delegate; }
 
   // Writes |packet| to the socket and returns the error code from the write.
-  int WritePacketToSocket(StringIOBuffer* packet);
+  WriteResult WritePacketToSocket(scoped_refptr<StringIOBuffer> packet);
 
   // QuicPacketWriter
   WriteResult WritePacket(const char* buffer,
                           size_t buf_len,
                           const IPAddress& self_address,
                           const IPEndPoint& peer_address,
                           PerPacketOptions* options) override;
   bool IsWriteBlockedDataBuffered() const override;
   bool IsWriteBlocked() const override;
   void SetWritable() override;
@@ skipping 15 matching lines @@
   bool write_blocked_;
 
   base::WeakPtrFactory<QuicChromiumPacketWriter> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicChromiumPacketWriter);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_CHROMIUM_PACKET_WRITER_H_