
Workaround behavior of goog.ui.Checkbox::toggle() which toggles undeterminate->checked, whereas we prefer undetermined->UNchecked.

The reason being that a common workflow is to select n items (checkbox is now in undetermined state), perform an action on them (like mark-as-read), and then to unselect these items with a single click on the checkbox.

R=chrishenry,nnaze
DELTA=34  (17 added, 16 deleted, 1 changed)


Revision created by MOE tool push_codebase.
MOE_MIGRATION=2696


yamadatomonori/closure-library,yamadatomonori/closure-library,yamadatomonori/closure-library