Method Iterator

tests/gtest/gtest.h:10616–10618

  class Iterator : public ParamIteratorInterface<T> {
   public:
    Iterator(const ParamGeneratorInterface<T>* base, T value, int index,
             IncrementT step)
        : base_(base), value_(value), index_(index), step_(step) {}
    ~Iterator() override {}

    const ParamGeneratorInterface<T>* BaseGenerator() const override {