Added a default background colour of black to the stick-person (:host) so that if the user doesn't specify a background colour then the stick-person is still visible (otherwise the default is rgb(0, 0, 0, 0) and the stick-person is transparent).
Added a default background colour of black to the stick-person (:host) so that if the user doesn't specify a background colour then the stick-person is still visible (otherwise the default is rgb(0, 0, 0, 0) and the stick-person is transparent).

R=mikelawther@chromium.org

Review URL: https://codereview.appspot.com/50300043

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