[SPDY] Use WeakPtr<SpdySession> everywhere but SpdySessionPool

net/http/http_stream_factory_impl_job.h

Index: net/http/http_stream_factory_impl_job.h
diff --git a/net/http/http_stream_factory_impl_job.h b/net/http/http_stream_factory_impl_job.h
index 6e34f5fe08581503073fecb92e8a658a56d3c204..2c2eb3495860690971188831303fe9672c670bec 100644
--- a/net/http/http_stream_factory_impl_job.h
+++ b/net/http/http_stream_factory_impl_job.h
@@ -307,10 +307,10 @@ class HttpStreamFactoryImpl::Job {
   int num_streams_;
 
   // Initialized when we create a new SpdySession.
-  scoped_refptr<SpdySession> new_spdy_session_;
+  base::WeakPtr<SpdySession> new_spdy_session_;
 
   // Initialized when we have an existing SpdySession.
-  scoped_refptr<SpdySession> existing_spdy_session_;
+  base::WeakPtr<SpdySession> existing_spdy_session_;
 
   // Only used if |new_spdy_session_| is non-NULL.
   bool spdy_session_direct_;