bug#16178: 24.3.50; eww: S-SPC scrolls downward not upward

[Rudolf Schlatte]

When pressing S-SPC (shift-Space) when viewing a web page in EWW, the
buffer scrolls downwards.  This is different from Info, View and other
display modes, where S-SPC scrolls upwards.

In GNU Emacs 24.3.50.4 (i386-apple-darwin13.0.0, NS apple-appkit-1265.00)
 of 2013-12-17 on buckaroo
Windowing system distributor `Apple', version 10.3.1265
Configured using:
 `configure --with-ns'

Important settings:
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: eww

Minor modes in effect:
  shell-dirtrack-mode: t
  TeX-PDF-mode: t
  show-paren-mode: t
  recentf-mode: t
  icomplete-mode: t
  desktop-save-mode: t
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  size-indication-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
C-n C-a <return> <return> <help-echo> <help-echo> <down-mouse-1> 
<mouse-1> <help-echo> <down-mouse-1> <drag-mouse-1> 
C-x C-s y C-n C-l C-1 C-l M-` C-c C-c y y M-` C-x b 
m e s s <return> M-< C-x k <return> <down-mouse-1> 
C-x C-s y M-` C-c C-c y y M-` <help-echo> <down-mouse-1> 
C-x C-s y C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n 
C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n 
C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-l C-n C-n 
C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n 
C-n C-n C-l C-x k <return> M-x c u s t o m i z e - 
v a r <tab> <return> m a i l - s e n d <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> s m t p m a i l 
- <tab> <M-backspace> m a i l - <tab> C-g C-x C-f ~ 
/ . e m a c s <return> M-< C-g C-s m a i l C-s C-s 
C-s C-s C-s C-s C-s C-n C-p C-l M-x c u s t o m i z 
- e <backspace> <backspace> e - v a r <tab> <return> 
s e n d - m a i <tab> <return> <help-echo> <down-mouse-1> 
<mouse-1> C-x C-s M-` C-c C-c y y M-` C-p C-p C-p C-p 
C-p C-p C-p <return> C-x C-s M-` C-c C-c y y M-` C-n 
C-n C-n C-n <return> C-x C-s M-` C-n C-n C-n C-n C-n 
C-n C-a C-SPC C-n C-n C-n M-w C-x C-g C-x k <return> 
y S-SPC C-x o C-x k <return> C-x o C-x 1 M-` C-n C-n 
C-n <return> C-x C-s y M-` M-x r e p o r t - e m <tab> 
<return>

Recent messages:
network-stream-command: Process smtpmail not running
Saving file /Users/rudi/.emacs...
Wrote /Users/rudi/.emacs [2 times]
Auto-saving...done
Mark activated
C-x C-g is undefined
Buffer *unsent mail to bug-gnu-emacs@gnu.org* modified; kill anyway? (y or n)  y
Mark set
Saving file /Users/rudi/.emacs...
Wrote /Users/rudi/.emacs [2 times]
Custom-no-edit: You can't edit this part of the Custom buffer

Load-path shadows:
~/Dropbox/Source/abstools/emacs/maude-mode hides 
~/BTSync/Source/elisp/maude-mode/maude-mode
~/BTSync/Source/elisp/org-mode/contrib/lisp/htmlize hides 
~/BTSync/Source/elisp/htmlize
~/BTSync/Source/elisp/magit/.dir-locals hides 
/Users/rudi/Applications/Emacs.app/Contents/Resources/lisp/gnus/.dir-locals

Features:
(misearch multi-isearch footnote uudecode uce time supercite regi
spam-report spam spam-stat gnus-uu yenc gnus-msg gnus-art mm-uu mml2015
epg-config mm-view mml-smime smime gnus-sum nnoo gnus-group gnus-undo
nnmail mail-source gnus-start gnus-spec gnus-int gnus-range gnus-win
sieve-manage rmail pop3 mspools mh-e mh-compat mh-acros mh-buffers
mh-loaddefs metamail mairix mailclient mail-hist imap hashcash
gnus-dired fortune feedmail ecomplete binhex w32-vars ebnf2ps ps-print
ps-def lpr dos-vars tramp tramp-compat tramp-loaddefs trampver shell
netrc net-utils ldap gravatar goto-addr dig bug-reference ange-ftp
mailalias smtpmail shadow sort mail-extr emacsbug message rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mailabbrev gmm-utils mailheader
sendmail shr-color color help-mode url-queue network-stream starttls
url-cache eww mm-url shr markdown-mode ruby-mode abs-mode sh-script smie
cc-langs cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align
cc-engine cc-vars cc-defs ox-texinfo ox-odt rng-loc rng-uri rng-parse
rng-match rng-dt rng-util rng-pttrn nxml-parse nxml-ns nxml-enc xmltok
nxml-util ox-md ox-html ox-beamer ox-latex ox-ascii ox-publish ox info
org-element tex-buf font-latex latex tex-style tex dbus xml view
dired-aux maude-mode rx vc-git eldoc slime-xref-browser slime-scratch
slime-package-fu slime-indentation slime-hyperdoc url-http tls url
url-proxy url-privacy url-expand url-methods url-history mailcap
url-auth mail-parse rfc2231 rfc2047 rfc2045 ietf-drums url-cookie
url-domsuf url-util url-parse auth-source eieio eieio-core
password-cache url-gw url-vars slime-fuzzy slime-fontifying-fu
slime-fancy-inspector slime-compiler-notes-tree slime-c-p-c
slime-editing-commands slime-banner slime-autodoc slime-parse slime-asdf
slime-repl elp slime derived pp hyperspec thingatpt paredit imenu
saveplace org-mac-link org-info org-docview doc-view jka-compr
image-mode dired org-bibtex bibtex paren recentf tree-widget ido
icomplete grep compile gnus gnus-ems nnheader gnus-util mail-utils
mm-util mail-prsvr desktop frameset o-blog o-blog-bootstrap o-blog-i18n
o-blog-grid o-blog-source o-blog-alert time-stamp html2text sgml-mode
ob-ditaa browse-url htmlize org-mouse pbook slime-autoloads eudcb-mab
executable eudc cus-edit cus-start cus-load eudc-vars wid-edit cl-macs
gv tex-site ls-lisp ert ewoc debug cl org-protocol org byte-opt bytecomp
byte-compile cconv advice help-fns org-macro org-footnote org-pcomplete
pcomplete org-list org-faces org-entities noutline outline easy-mmode
org-version ob-emacs-lisp ob ob-tangle org-src ob-ref ob-lob ob-table
ob-keys ob-exp ob-comint comint ansi-color ring ob-core ob-eval
org-compat org-macs org-loaddefs format-spec find-func cal-menu easymenu
calendar cal-loaddefs server vc vc-dispatcher docbook-autoloads package
edmacro kmacro cl-loaddefs cl-lib time-date tooltip electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel ns-win tool-bar dnd fontset
image regexp-opt fringe tabulated-list newcomment lisp-mode prog-mode
register page menu-bar rfn-eshadow timer select scroll-bar mouse
jit-lock font-lock syntax facemenu font-core frame cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev
minibuffer nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
cocoa ns multi-tty emacs)