Starts the view animation.
function _initShowAnimation(item, prevItem, size) {
        var spec = item.options.show.animation ? item.options.show.animation.call(undefined, true, size) : {};
        item.startSpec = spec;
        item.endSpec = {
            opacity: 1,
            transform: Transform.identity
        };
        item.mod.halt();
        if (spec.transform) {
            item.mod.setTransform(spec.transform);
        }
        if (spec.opacity !== undefined) {
            item.mod.setOpacity(spec.opacity);
        }
        if (spec.align) {
            item.mod.setAlign(spec.align);
        }
        if (spec.origin) {
            item.mod.setOrigin(spec.origin);
        }
        var startShowAnimation = _startShowAnimation.bind(this, item, spec);
        var waitAndShow = item.wait ? function() {
            item.wait.then(startShowAnimation, startShowAnimation);
        } : startShowAnimation;
        if (prevItem) {
            _initTransferableAnimations.call(this, item, prevItem, waitAndShow);
        }
        else {
            waitAndShow();
        }
    }