bug#19270: 25.0.50; Make PDF Mode in EWW customizable

[Sebastian Wiesner]

> Am 04.12.2014 um 17:20 schrieb Stefan Monnier <monnier@iro.umontreal.ca>:
> 
>> Currently EWW uses `doc-view-mode' to view PDF data.  This choice is
>> hard-coded in `eww-display-pdf' and cannot be customized.
> 
> I wonder: do you sometimes prefer doc-view-mode?
> 
> If not, then rather than configuring EWW, you'd probably be better off
> with a way to configure Emacs to always use my-pdf-mode for PDF files.

That's not possible either.  As I said, it's hard-coded in EWW currently.

> IOW, maybe adding configurability to EWW is good in itself, but I think
> your use case would be better served by a config elsewhere, which would
> cover EWW as well as other cases where we might want to view PDF files.

Well, whatever way you want, but just add a way to tell EWW what to use for 
PDFs.

But do we really need a new setting?  I don't know EWW, so please excuse me, if 
I'm asking a stupid question, but why does EWW not rely on `auto-mode-alist'?  
Instead of using a generic buffer without a file name, it could create a 
separate buffer and set it's name and file name according to the URL of the PDF 
file, and then just use `set-auto-mode'.  Would that work, or am I missing 
something?