Remove useless references to unsupported windows versions (3)

This CL goes over the content/ directory.

Bug: 579196, 304193
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_site_isolation
Change-Id: I8e87c220e424ff469c42abc09fa86746176b1812
Reviewed-on: https://chromium-review.googlesource.com/565944
Reviewed-by: James Forshaw <forshaw@chromium.org>
Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Commit-Queue: Patrick Monette <pmonette@chromium.org>
Cr-Commit-Position: refs/heads/master@{#486891}
7 files changed