Fix strong-mode errors in directives_test.
Fix strong-mode errors in directives_test.

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kevmoo/angular,kevmoo/angular,chalin/angular2,kevmoo/angular,matanlurey/angular,matanlurey/angular,chalin/angular2,angulardart/angular,angulardart/angular,angulardart/angular,chalin/angular2,matanlurey/angular