[fixed] type signature on log
[fixed] type signature on log

Reviewers: O2 Material Motion, O3 Material JavaScript platform reviewers, #material_motion, markwei

Reviewed By: O2 Material Motion, #material_motion, markwei

Tags: #material_motion

Differential Revision: http://codereview.cc/D3295

material-motion/material-motion-js,material-motion/material-motion-js,material-motion/material-motion-js