Refactor QuicServerSessionBase::Visitor

net/quic/core/quic_session.h

Index: net/quic/core/quic_session.h
diff --git a/net/quic/core/quic_session.h b/net/quic/core/quic_session.h
index 7425732965513c9b5c564118bee0c6cc7c8c221b..7d8818b319c8f62442696302550db5b05b1b003d 100644
--- a/net/quic/core/quic_session.h
+++ b/net/quic/core/quic_session.h
@@ -41,6 +41,22 @@ class QuicSessionPeer;
 
 class NET_EXPORT_PRIVATE QuicSession : public QuicConnectionVisitorInterface {
  public:
+  // An interface from the session to the entity owning the session.
+  // This lets the session notify its owner (the Dispatcher) when the connection
+  // is closed, blocked, or added/removed from the time-wait std::list.
+  class Visitor {
+   public:
+    virtual ~Visitor() {}
+
+    // Called when the connection is closed after the streams have been closed.
+    virtual void OnConnectionClosed(QuicConnectionId connection_id,
+                                    QuicErrorCode error,
+                                    const std::string& error_details) = 0;
+
+    // Called when the session has become write blocked.
+    virtual void OnWriteBlocked(QuicBlockedWriterInterface* blocked_writer) = 0;
+  };
+
   // CryptoHandshakeEvent enumerates the events generated by a QuicCryptoStream.
   enum CryptoHandshakeEvent {
     // ENCRYPTION_FIRST_ESTABLISHED indicates that a full client hello has been
@@ -58,8 +74,10 @@ class NET_EXPORT_PRIVATE QuicSession : public QuicConnectionVisitorInterface {
     HANDSHAKE_CONFIRMED,
   };
 
-  // Does not take ownership of |connection|.
-  QuicSession(QuicConnection* connection, const QuicConfig& config);
+  // Does not take ownership of |connection| or |visitor|.
+  QuicSession(QuicConnection* connection,
+              Visitor* owner,
+              const QuicConfig& config);
 
   ~QuicSession() override;
 
@@ -74,7 +92,7 @@ class NET_EXPORT_PRIVATE QuicSession : public QuicConnectionVisitorInterface {
   void OnConnectionClosed(QuicErrorCode error,
                           const std::string& error_details,
                           ConnectionCloseSource source) override;
-  void OnWriteBlocked() override {}
+  void OnWriteBlocked() override;
   void OnSuccessfulVersionNegotiation(const QuicVersion& version) override;
   void OnCanWrite() override;
   void OnCongestionWindowChange(QuicTime /*now*/) override {}
@@ -337,6 +355,10 @@ class NET_EXPORT_PRIVATE QuicSession : public QuicConnectionVisitorInterface {
   virtual void HandleRstOnValidNonexistentStream(
       const QuicRstStreamFrame& frame);
 
+  Visitor* visitor() { return visitor_; }
+
+  const Visitor* visitor() const { return visitor_; }
+
  private:
   friend class test::QuicSessionPeer;
 
@@ -361,6 +383,9 @@ class NET_EXPORT_PRIVATE QuicSession : public QuicConnectionVisitorInterface {
 
   QuicConnection* connection_;
 
+  // May be null.
+  Visitor* visitor_;
+
   ClosedStreams closed_streams_;
 
   QuicConfig config_;