Merge "check for null members in NotifyHandler" into nyc-dev

void NotifyHandler::handleMessage(const Message& message) {

    JNIEnv* env = getenv(mVm);

    jobject target = env->NewLocalRef(mObserver->getObserverReference());

    ObserverProxy* observer = mObserver.get();

    LOG_ALWAYS_FATAL_IF(observer == nullptr, "received message with no observer configured");

    LOG_ALWAYS_FATAL_IF(mBuffer == nullptr, "received message with no data to report");

    jobject target = env->NewLocalRef(observer->getObserverReference());

    if (target != nullptr) {

        jlongArray javaBuffer = get_metrics_buffer(env, target);