Add a new QuicChromiumClientSession::Handle class

net/quic/chromium/quic_stream_factory.h

Index: net/quic/chromium/quic_stream_factory.h
diff --git a/net/quic/chromium/quic_stream_factory.h b/net/quic/chromium/quic_stream_factory.h
index 9feedb36b5eb6ce4b0698e856e9cf39deb8cff7d..2e92ca0c1464828781fec2f910cefd5608c9af9d 100644
--- a/net/quic/chromium/quic_stream_factory.h
+++ b/net/quic/chromium/quic_stream_factory.h
@@ -135,7 +135,7 @@ class NET_EXPORT_PRIVATE QuicStreamRequest {
   std::unique_ptr<BidirectionalStreamImpl> CreateBidirectionalStreamImpl();
 
   // Sets |session_|.
-  void SetSession(QuicChromiumClientSession* session);
+  void SetSession(const QuicChromiumClientSession::Handle& session);

[xunjieli, 2017/05/04 16:54:42]

I think for simplicity we should keep this as QuicChromiumClientSession,
otherwise the concept of a handle gets rather complicated. Each
BidiStream/HttpStream holds a Handle to the session, but each
QuicStreamFactory::QuicStreamRequest can also take a copy of
QuicChromiumClientSession's self handle. The Handle of
QuicStreamFactory::QuicStreamRequest is also not passed to
BidiStream/HttpStream. 

[Ryan Hamilton, 2017/05/04 18:45:53]

Hm. I'm not sure I follow you. My vision (perhaps poorly thought out) is that
everything that needs to talk to a session (with the exception of the
QuicStreamFactory which owns the session) should use a Handle to it.

Perhaps we can chat about this design?

 
   const QuicServerId& server_id() const { return server_id_; }
 
@@ -147,7 +147,7 @@ class NET_EXPORT_PRIVATE QuicStreamRequest {
   QuicServerId server_id_;
   NetLogWithSource net_log_;
   CompletionCallback callback_;
-  base::WeakPtr<QuicChromiumClientSession> session_;
+  std::unique_ptr<QuicChromiumClientSession::Handle> session_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicStreamRequest);
 };