native scrolling for xwidget webkit

[joakim]

So, I finally got around to implement native scrolling for the webkit
xwidget.

(For those that havent tried the branch, this mail probably feels like
line noise. Sorry for that)


If someone would like to try the native scrolling:
- compile the branch: ./configure --with-xwidgets  --with-x-toolkit=gtk3
&& make -j4

- browse a site: M-x xwidget-browse-url RET www.fsf.org RET

by default the webkit uses Emacs scrolling, which isnt too bad, but
crashes if the height of the page is too big.

- make the webkit widget smaller: m-x xwidget-webkit-adjust-size RET 500
  RET 500 RET

the webkit is now smaller and has native scrollbars, but you cant drag
them for obscure gtk reasons. Instead you must set scrolling with an
api:

m-: (xwidget-set-adjustment (xwidget-at 1) 'vertical t 50)

This will increase scrolling by 50, relatively, vertical.




-- 
Joakim Verona