This is the other side of https://codereview.chromium.org/1163723003/

The changes here are to remove the use of 'vs2013_files' and 'win8sdk'
(as those will be different numbers soon enough) but still maintain
behaviour for the old "style" while in transition.

Secondarily, to remove the dependence of these two scripts on
'toolchain2013.py' as most of the script is now unused.

R=dpranke@chromium.org
BUG=440500, 492774

Review URL: https://codereview.chromium.org/1165563003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@295485 0039d316-1c4b-4281-b951-d872f2087c98