Revert 247156 "Revert 247151 "Cleanup of windows launch code""

This re-enables 247151 because I can't repro it
so it is possible it was a temporary NaCL insanity and definitely
the x64 breakage was a flake as confirmed by try jobs.


> Revert 247151 "Cleanup of windows launch code"
> 
> > Cleanup of windows launch code
> > 
> > The windows startup code was handling aura and non-aura cases which
> > require different startup logic in metro (immersive mode). Since we
> > don't support the non-Aura logic we can get rid of a lot of code.
> > 
> > Tbring gab for the installer constant addition.
> > 
> > R=ananta@chromium.org, scottmg@chromium.org
> > TBR=gab
> > BUG=none
> > 
> > Review URL: https://codereview.chromium.org/142473002
> 
> TBR=cpu@chromium.org
> 
> Review URL: https://codereview.chromium.org/140123006

TBR=cpu@chromium.org

Review URL: https://codereview.chromium.org/151683004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248331 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248331