Add perspective_ member for QuicStream.

This change is in favor of removing session access from stream.

gfe-relnote: no behavior change. Not protected.
PiperOrigin-RevId: 295011376
Change-Id: Ie6a9f899a52bbc1c7ae4eda149259bbc40dba95d
diff --git a/quic/core/quic_stream.h b/quic/core/quic_stream.h
index c182031..933c77a 100644
--- a/quic/core/quic_stream.h
+++ b/quic/core/quic_stream.h
@@ -535,6 +535,8 @@
   // Indicates whether this stream is bidirectional, read unidirectional or
   // write unidirectional.
   const StreamType type_;
+
+  Perspective perspective_;
 };
 
 }  // namespace quic