Collect all ConnectionAttempts from both sockets in TransportConnectJob.

net/socket/client_socket_handle.h

Index: net/socket/client_socket_handle.h
diff --git a/net/socket/client_socket_handle.h b/net/socket/client_socket_handle.h
index 58cf4ca6709b8d72c9fb86193142cd25d8409fc2..2f8bed2080b8e6dcacf67028a695284aecc273b1 100644
--- a/net/socket/client_socket_handle.h
+++ b/net/socket/client_socket_handle.h
@@ -156,6 +156,9 @@ class NET_EXPORT ClientSocketHandle {
   ClientSocketHandle* release_pending_http_proxy_connection() {
     return pending_http_proxy_connection_.release();
   }
+  // If the connection failed, returns the connection attempts made. (If it
+  // succeeded, they will be returned through the socket instead; see
+  // |StreamSocket::GetConnectionAttempts|.)
   const ConnectionAttempts& connection_attempts() {
     return connection_attempts_;
   }