Remove references to non-Aura Win WebThemeEngine implementation.

R=jamesr@chromium.org, piman@chromium.org
BUG=327471, 330735

Review URL: https://codereview.chromium.org/154643005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250510 0039d316-1c4b-4281-b951-d872f2087c98
Set -fmsc-version for the Windows Clang build

It's important that -fmsc-version matches the version of VS that we're
falling back to. In practive, this should always be 2013 these days.

BUG=82385
NOTRY=true

Review URL: https://codereview.chromium.org/151663004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250511 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250511