Change tui_line_is_displayed to be a method

This changes tui_line_is_displayed to be a method on
tui_source_window, now that it is obvious that it can only be called
for this type.

gdb/ChangeLog
2019-08-15  Tom Tromey  <tom@tromey.com>

	* tui/tui-winsource.h (tui_line_is_displayed): Don't declare.
	* tui/tui-winsource.c (tui_line_is_displayed): Move to
	tui-source.c.
	* tui/tui-source.h (struct tui_source_window) <line_is_displayed>:
	Declare.
	* tui/tui-source.c (tui_source_window::line_is_displayed): New
	method.
	(tui_source_window::maybe_update): Update.

gdb/ChangeLog

@@ -1,3 +1,14 @@
+2019-08-15  Tom Tromey  <tom@tromey.com>
+
+	* tui/tui-winsource.h (tui_line_is_displayed): Don't declare.
+	* tui/tui-winsource.c (tui_line_is_displayed): Move to
+	tui-source.c.
+	* tui/tui-source.h (struct tui_source_window) <line_is_displayed>:
+	Declare.
+	* tui/tui-source.c (tui_source_window::line_is_displayed): New
+	method.
+	(tui_source_window::maybe_update): Update.
+
 2019-08-15  Tom Tromey  <tom@tromey.com>
 
 	* tui/tui-winsource.h (tui_addr_is_displayed): Don't declare.

gdb/tui/tui-source.c

@@ -294,6 +294,25 @@ tui_source_window::location_matches_p (struct bp_location *loc, int line_no)
 			   symtab_to_fullname (loc->symtab)) == 0);
 }
 
+/* See tui-source.h.  */
+
+bool
+tui_source_window::line_is_displayed (int line) const
+{
+  bool is_displayed = false;
+  int threshold = SCROLL_THRESHOLD;
+  int i = 0;
+  while (i < content.size () - threshold && !is_displayed)
+    {
+      is_displayed
+	= (content[i].line_or_addr.loa == LOA_LINE
+	   && content[i].line_or_addr.u.line_no == line);
+      i++;
+    }
+
+  return is_displayed;
+}
+
 void
 tui_source_window::maybe_update (struct frame_info *fi, symtab_and_line sal,
 				 int line_no, CORE_ADDR addr)
@@ -310,7 +329,7 @@ tui_source_window::maybe_update (struct frame_info *fi, symtab_and_line sal,
   l.loa = LOA_LINE;
   l.u.line_no = start_line;
   if (!(source_already_displayed
-	&& tui_line_is_displayed (line_no, this, TRUE)))
+	&& line_is_displayed (line_no)))
     tui_update_source_window (this, get_frame_arch (fi),
 			      sal.symtab, l, TRUE);
   else

gdb/tui/tui-source.h

@@ -59,6 +59,10 @@ private:
 
   void style_changed ();
 
+  /* Answer whether a particular line number or address is displayed
+     in the current source window.  */
+  bool line_is_displayed (int line) const;
+
   /* A token used to register and unregister an observer.  */
   gdb::observers::token m_observable;
 };

gdb/tui/tui-winsource.c

@@ -640,31 +640,3 @@ tui_alloc_source_buffer (struct tui_source_window_base *win_info)
 	win_info->content[i].line = (char *) xmalloc (line_width);
     }
 }
-
-
-/* Answer whether a particular line number or address is displayed
-   in the current source window.  */
-int
-tui_line_is_displayed (int line, 
-		       struct tui_source_window_base *win_info,
-		       int check_threshold)
-{
-  int is_displayed = FALSE;
-  int i, threshold;
-
-  if (check_threshold)
-    threshold = SCROLL_THRESHOLD;
-  else
-    threshold = 0;
-  i = 0;
-  while (i < win_info->content.size () - threshold
-	 && !is_displayed)
-    {
-      is_displayed
-	= win_info->content[i].line_or_addr.loa == LOA_LINE
-	  && win_info->content[i].line_or_addr.u.line_no == line;
-      i++;
-    }
-
-  return is_displayed;
-}

gdb/tui/tui-winsource.h

@@ -174,9 +174,6 @@ extern void tui_clear_source_content (struct tui_source_window_base *);
 extern void tui_erase_source_content (struct tui_source_window_base *);
 
 extern void tui_alloc_source_buffer (struct tui_source_window_base *);
-extern int tui_line_is_displayed (int,
-				  struct tui_source_window_base *,
-				  int);
 
 
 /* Constant definitions. */