void ContentDistributor::distribute(Element* host)
{
    ASSERT(needsDistribution());
    ASSERT(m_nodeToInsertionPoint.isEmpty());

    m_validity = Valid;

    ContentDistribution pool;
    for (Node* node = host->firstChild(); node; node = node->nextSibling())
        populate(node, pool);

    Vector<bool> distributed(pool.size());
    distributed.fill(false);

    Vector<HTMLShadowElement*, 8> activeShadowInsertionPoints;
    for (ShadowRoot* root = host->youngestShadowRoot(); root; root = root->olderShadowRoot()) {
        HTMLShadowElement* firstActiveShadowInsertionPoint = 0;

        const Vector<InsertionPoint*>& insertionPoints = root->insertionPointList();
        for (size_t i = 0; i < insertionPoints.size(); ++i) {
            InsertionPoint* point = insertionPoints[i];
            if (!point->isActive())
                continue;

            if (isHTMLShadowElement(point)) {
                if (!firstActiveShadowInsertionPoint)
                    firstActiveShadowInsertionPoint = toHTMLShadowElement(point);
            } else {
                distributeSelectionsTo(point, pool, distributed);
                if (ElementShadow* shadow = point->parentNode()->isElementNode() ? toElement(point->parentNode())->shadow() : 0)
                    shadow->invalidateDistribution();
            }
        }

        if (firstActiveShadowInsertionPoint)
            activeShadowInsertionPoints.append(firstActiveShadowInsertionPoint);
    }

    for (size_t i = activeShadowInsertionPoints.size(); i > 0; --i) {
        HTMLShadowElement* shadowElement = activeShadowInsertionPoints[i - 1];
        ShadowRoot* root = shadowElement->shadowRoot();
        ASSERT(root);
        if (root->olderShadowRoot()) {
            distributeNodeChildrenTo(shadowElement, root->olderShadowRoot());
            root->olderShadowRoot()->setAssignedTo(shadowElement);
        } else {
            distributeSelectionsTo(shadowElement, pool, distributed);
            if (ElementShadow* shadow = shadowElement->parentNode()->isElementNode() ? toElement(shadowElement->parentNode())->shadow() : 0)
                shadow->invalidateDistribution();
        }
    }
}
bool ContentDistributor::invalidate(Element* host)
{
    ASSERT(needsInvalidation());
    bool needsReattach = (m_validity == Undetermined) || !m_nodeToInsertionPoint.isEmpty();

    for (ShadowRoot* root = host->youngestShadowRoot(); root; root = root->olderShadowRoot()) {
        root->setAssignedTo(0);
        const Vector<InsertionPoint*>& insertionPoints = root->insertionPointList();
        for (size_t i = 0; i < insertionPoints.size(); ++i) {
            needsReattach = needsReattach || true;
            insertionPoints[i]->clearDistribution();
        }
    }

    m_validity = Invalidating;
    m_nodeToInsertionPoint.clear();
    return needsReattach;
}