Created attachment 146211 [details] [review]
[GenericDisplay] Only do redisplay when mapped

Created attachment 146228 [details] [review]
[GenericDisplay] Only do redisplay when mapped

If we're not mapped, only queue up a redisplay.  This avoids
e.g. changes in recent documents such as saving a file in GEdit
causing a lot of blocking I/O in the shell (we need to make
recent loading async as well).

Comment on attachment 146228 [details] [review]
[GenericDisplay] Only do redisplay when mapped

>     _redisplay: function(flags) {
>+        if (!this._list.mapped) {
>+            this._pendingRedisplay |= flags;
>+            return;
>+        }
>+
>         let isSubSearch = (flags & RedisplayFlags.SUBSEARCH) > 0;
>         let fullReload = (flags & RedisplayFlags.FULL) > 0;
>         let resetPage = (flags & RedisplayFlags.RESET_CONTROLS) > 0 || fullReload;
> 
>+        this._pendingRedisplay = RedisplayFlags.NONE;

This looks like it's a bug; you set isSubSearch etc based on flags but then clear _pendingRedisplay. Of course, after looking at _onMappedNotify I see that it is actually correct, but it's confusing. I think it would be better to clear this._pendingRedisplay from _onMappedNotify.

OK to commit with that change.