// Makes a list of widgets and asynchronously frobnicates them.
//
// WTF::Vector promises that iterators remain valid unless the vector is mutated,
// so this was previously legal code. It becomes illegal if compaction moves the
// backing allocation.
class Frobnicator : public GarbageCollected<Frobnicator> {
 public:
  Frobnicator() {
    // populate m_widgets with some widgets
    m_iterator = m_widgets.begin();
  }

  void frobnicate() {
    for (; m_iterator != m_widgets.end(); ++m_iterator) {
      if (shouldYield()) {
        postTask(WTF::bind(&Frobnicator::frobnicate, WTF::makePersistent(this)));
        return;
      }
      (*m_iterator)->frobnicate();
    }
  }

 private:
  bool shouldYield() const;

  HeapVector<Widget> m_widgets;
  HeapVector<Widget>::iterator m_iterator;
};