Remove ui::num

I noticed that nothing uses ui::num, so this patch removes it.

gdb/ChangeLog
2020-09-15  Tom Tromey  <tromey@adacore.com>

	* top.c (ui::ui): Update.
	(highest_ui_num): Remove.
	* top.h (struct ui) <num>: Remove.

3 files changed, 6 insertions, 7 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index fe19f19..7481416 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,11 @@
 2020-09-15  Tom Tromey  <tromey@adacore.com>
 
+	* top.c (ui::ui): Update.
+	(highest_ui_num): Remove.
+	* top.h (struct ui) <num>: Remove.
+
+2020-09-15  Tom Tromey  <tromey@adacore.com>
+
 	* unittests/memory-map-selftests.c (valid_mem_map): Now array.
 	* ui-style.c (ansi_regex_text): Now array.
 	* rust-exp.y (number_regex_text): Now array.
diff --git a/gdb/top.c b/gdb/top.c
index acd31af..8dbc7ce 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -270,14 +270,10 @@ void (*deprecated_call_command_hook) (struct cmd_list_element * c,
 
 void (*deprecated_context_hook) (int id);
 
-/* The highest UI number ever assigned.  */
-static int highest_ui_num;
-
 /* See top.h.  */
 
 ui::ui (FILE *instream_, FILE *outstream_, FILE *errstream_)
   : next (nullptr),
-    num (++highest_ui_num),
     call_readline (nullptr),
     input_handler (nullptr),
     command_editing (0),
diff --git a/gdb/top.h b/gdb/top.h
index fd99297..92b0964 100644
--- a/gdb/top.h
+++ b/gdb/top.h
@@ -65,9 +65,6 @@ struct ui
   /* Pointer to next in singly-linked list.  */
   struct ui *next;
 
-  /* Convenient handle (UI number).  Unique across all UIs.  */
-  int num;
-
   /* The UI's command line buffer.  This is to used to accumulate
      input until we have a whole command line.  */
   struct buffer line_buffer;