Don't use deprecated EventListener class.

Author: ehsannas

firestore/testapp/src/common_main.cc

@@ -59,34 +59,26 @@ class Countable {
  int event_count_ = 0;
 };
 
-template <typename T>
-class TestEventListener : public Countable,
- public firebase::firestore::EventListener<T> {
+template <typename T> class TestEventListener : public Countable {
 public:
  explicit TestEventListener(std::string name) : name_(std::move(name)) {}
 
  void OnEvent(const T &value, const firebase::firestore::Error error_code,
- const std::string &error_message) override {
+ const std::string &error_message) {
  event_count_++;
  if (error_code != firebase::firestore::kErrorOk) {
  LogMessage("ERROR: EventListener %s got %d (%s).", name_.c_str(),
  error_code, error_message.c_str());
  }
  }
 
- // Hides the STLPort-related quirk that `AddSnapshotListener` has different
- // signatures depending on whether `std::function` is available.
  template <typename U>
  firebase::firestore::ListenerRegistration AttachTo(U *ref) {
-#if !defined(STLPORT)
  return ref->AddSnapshotListener(
  [this](const T &result, firebase::firestore::Error error_code,
  const std::string &error_message) {
  OnEvent(result, error_code, error_message);
  });
-#else
- return ref->AddSnapshotListener(this);
-#endif
  }
 
 private: