move the for-loops in tick() to another method so they can be optimized
move the for-loops in tick() to another method so they can be optimized

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=150354372

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