bug#12915: 24.2.50; Visiting a file via drag-and-drop should add it to the history ofvisited files

[Drew Adams]

> Maybe a more automatic way

More automatic is even worse.  _User interaction_ (mainly, typing a name) should
control whether an _input history_ gets augmented.

That should not happen automatically each time a file is displayed (or a
variable's doc is shown, or a function is called that might happen to be a
command, or...)

> is to provide a `display-buffer-hook', that's
> run from `set-window-buffer', and then have 
> find-file-noselect use this hook to add the file
> name onto the history if the buffer is shown to
> the user.

It's not clear whether you are actually suggesting that the file name should be
added unconditionally whenever the file is displayed.

If you are, that's the worst possible thing, IMO.  Just because a file is
displayed does not mean that a user wants that name to be added to the input
history for file names.

It's a file-name _input_ history - generalized at most to a
user-request-for-the-file history.  It is not just a file-display history.