Revert 232142 "Revert 230138 "Delay wallpaper load by 2 * averag..."
Broke Linux ChromiumOS Builder:
http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Builder/builds/57984/steps/compile/logs/stdio
> Revert 230138 "Delay wallpaper load by 2 * average wallpaper loa..."
>
> Reason: regression on zgb/alex/mario resulting in login UI being invisible in certain cases. See http://crbug.com/313019
>
> > Delay wallpaper load by 2 * average wallpaper load time.
> >
> > BUG=279102,313019
> >
> > TEST=manual
> >
> > Review URL: https://codereview.chromium.org/
24625003
>
> TBR=alemate@chromium.org
>
> Review URL: https://codereview.chromium.org/
54333005
TBR=nkostylev@chromium.org
Review URL: https://codereview.chromium.org/
54723003
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232146 0039d316-1c4b-4281-b951-d872f2087c98