Fix the layouting of the checkbox.

Sometimes (very rarely) the checkbox is not layouted correctly
(it's partly visible only). The reason is that the checkbox
(and the hint text below it) has layout_width set to
"wrap_content" as well, which means it needs more then one
layout runs to get the final layout.

Change-Id: I460bb29e2d9b4fdcf3df314e2baf9c45b2a6259b