bug#32932: 27.0.50; render bugs on macOS Mojave

[Aaron Jensen]

> On October 31, 2018 at 10:13:01 AM, Alan Third 
> (alan@idiocy.org(mailto:alan@idiocy.org)) wrote:
> > Something is blanking the line. There are only so many places where
> > that happens so in theory it should be relatively straight‐forward to
> > find the place in question. Perhaps start by commenting out the
> > NSRectFill commands in ns_clear_frame and ns_clear_frame_area.
>
> I commented out every single NSRectFill and it still did it. It’s fast, but 
> gif attached.
>
> I tried commenting out the setNeedsDisplay but that breaks rendering entirely.

This is a trace from when it happens with all groups enabled. Not sure
fi it helps...

nsterm.m  : 6202: [  517]  [EmacsView keyDown:]
nsimage.m :   61: [  518]  ns_image_for_XPM
nsterm.m  : 2352: [  519]  ns_lisp_to_color
nsterm.m  : 2231: [  520]  | ns_get_color(#FFEB95, **)
nsterm.m  : 3172: [  521]  ns_draw_window_cursor
nsterm.m  : 3172: [  522]  ns_draw_window_cursor
nsterm.m  : 3172: [  523]  ns_draw_window_cursor
nsterm.m  : 1245: [  524]  | ns_clip_to_rect
nsterm.m  : 1248: [  525]  | +--- r: (X:464 Y:76)/(W:8 H:19)
nsterm.m  : 1265: [  526]  | +--- r: (X:464 Y:76)/(W:8 H:19)
nsterm.m  : 3172: [  527]  ns_draw_window_cursor
nsfns.m   :  525: [  528]  x_implicitly_set_name
nsfns.m   :  475: [  529]  | ns_set_represented_filename
nsfns.m   :  432: [  530]  | ns_set_name
nsmenu.m  :  116: [  531]  ns_update_menubar
nsterm.m  : 4924: [  532]  ns_condemn_scroll_bars
nsterm.m  : 2352: [  533]  ns_lisp_to_color
nsterm.m  : 2231: [  534]  | ns_get_color(#ffffffffffff, **)
nsterm.m  : 2352: [  535]  ns_lisp_to_color
nsterm.m  : 2231: [  536]  | ns_get_color(#FFEB95, **)
nsimage.m :   61: [  537]  ns_image_for_XPM
nsterm.m  : 4973: [  538]  ns_judge_scroll_bars