Upstream cpplint.py r79 ("Convert windows path seperators to unix like while doing IncludeWhatYouUse.")

Review URL: http://codereview.chromium.org/9159036

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@119713 0039d316-1c4b-4281-b951-d872f2087c98