[Mac] Resources for the new avatar button skin

BUG=305041
NOTRY=true
R=oshima@chromium.org

Review URL: https://codereview.chromium.org/153973002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248772 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248772