Rename 'source_' in QuicSession to 'connection_close_source_'.

PiperOrigin-RevId: 704743057
diff --git a/quiche/quic/core/quic_session.cc b/quiche/quic/core/quic_session.cc
index 55f8d3a..b91dbbd 100644
--- a/quiche/quic/core/quic_session.cc
+++ b/quiche/quic/core/quic_session.cc
@@ -585,7 +585,7 @@
   if (on_closed_frame_.quic_error_code == QUIC_NO_ERROR) {
     // Save all of the connection close information
     on_closed_frame_ = frame;
-    source_ = source;
+    connection_close_source_ = source;
   }
 
   GetMutableCryptoStream()->OnConnectionClosed(frame, source);
@@ -953,8 +953,8 @@
 std::string QuicSession::on_closed_frame_string() const {
   std::stringstream ss;
   ss << on_closed_frame_;
-  if (source_.has_value()) {
-    ss << " " << ConnectionCloseSourceToString(*source_);
+  if (connection_close_source_.has_value()) {
+    ss << " " << ConnectionCloseSourceToString(*connection_close_source_);
   }
   return ss.str();
 }
diff --git a/quiche/quic/core/quic_session.h b/quiche/quic/core/quic_session.h
index fee549a..b15dbac 100644
--- a/quiche/quic/core/quic_session.h
+++ b/quiche/quic/core/quic_session.h
@@ -1045,7 +1045,7 @@
 
   // Received information for a connection close.
   QuicConnectionCloseFrame on_closed_frame_;
-  std::optional<ConnectionCloseSource> source_;
+  std::optional<ConnectionCloseSource> connection_close_source_;
 
   // Used for connection-level flow control.
   QuicFlowController flow_controller_;