Fix ejecting if the element is not selected.

This patch fixes a recent regression, which was incorrectly taking the selection instead of the element the eject button is on.

TEST=Tested manually with archives.
BUG=337577

Review URL: https://codereview.chromium.org/131103020

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247696 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247696