unction (container, children) {
var composed = TreeApi.Composed.getChildNodes(container);
var splices = Polymer.ArraySplice.calculateSplices(children, composed);
for (var i = 0, d = 0, s; i < splices.length && (s = splices[i]); i++) {
for (var j = 0, n; j < s.removed.length && (n = s.removed[j]); j++) {
if (TreeApi.Composed.getParentNode(n) === container) {
TreeApi.Composed.removeChild(container, n);
}
composed.splice(s.index + d, 1);
}
d -= s.addedCount;
}
for (var i = 0, s, next; i < splices.length && (s 