Crash ao abrir o Mapa

Quando eu clico no link do mapa eu recebo a pergunta e o crash ao mesmo tempo. Se eu dou a permissão ele não dá o crash novamente, se eu nego a permissão então volta ao mesmo erro.

Detalhe que a tela da permissão fica por trás do aviso de crash e quando dou Ok no aviso ela vem para frente e fica o launcher atrás da tela de permissão.

package br.com.alura.agenda;

import android.content.pm.PackageManager;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.Manifest;

public class MapaActivity extends AppCompatActivity {

    private static final int REQUEST_PERMISSOES = 1;
    private MapaFragment mapaFragment;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_mapa);

        FragmentManager manager = getSupportFragmentManager();
        FragmentTransaction tx = manager.beginTransaction();

        mapaFragment = new MapaFragment();

        tx.replace(R.id.frame_mapa, mapaFragment);
        tx.commit();

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED
                    || ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                String[] permissoes = {Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION};
                requestPermissions(permissoes, REQUEST_PERMISSOES);
            }
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {

        if(requestCode == REQUEST_PERMISSOES){

            if(grantResults[0] == PackageManager.PERMISSION_GRANTED &&
                    grantResults[1] == PackageManager.PERMISSION_GRANTED){

                new Localizador(this, mapaFragment);
            }
        }
    }
}

 public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()){
            case R.id.menu_enviar_notas:
                new EnviaAlunosTask(this).execute();
                break;

            case R.id.menu_baixar_provas:
                Intent vaiParaProvas = new Intent(this, ProvasActivity.class);
                startActivity(vaiParaProvas);
                break;

            case R.id.menu_mapa:
                Intent vaiParaMapa = new Intent(this, MapaActivity.class);
                startActivity(vaiParaMapa);
                break;
        }

        return super.onOptionsItemSelected(item);

package br.com.alura.agenda;

import android.location.Address;
import android.location.Geocoder;
import android.os.Bundle;

import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

import java.io.IOException;
import java.util.List;

import br.com.alura.agenda.dao.AlunoDAO;
import br.com.alura.agenda.modelo.Aluno;

/**
 * Created by Rodrigo on 27/03/2017.
 */

public class MapaFragment extends SupportMapFragment implements OnMapReadyCallback {

    private GoogleMap mapa;

    @Override
    public void onCreate(Bundle bundle) {
        super.onCreate(bundle);

        getMapAsync(this);
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {

        this.mapa = googleMap;

        LatLng posicaoDaEscola = pegaCoordenadaDoEndereco("Rua Vergueiro 3185, Vila Mariana, Sao Paulo");

        if (posicaoDaEscola != null){
            centralizaEm(posicaoDaEscola);
        }

        //adiciona local do aluno
        AlunoDAO dao = new AlunoDAO(getContext());
        for(Aluno aluno : dao.buscaAlunos()){
            LatLng coordenada = pegaCoordenadaDoEndereco(aluno.getEndereco());
            if(coordenada != null) {
                MarkerOptions marcador = new MarkerOptions();
                marcador.position(coordenada);
                marcador.title(aluno.getNome());
                marcador.snippet(String.valueOf(aluno.getNota()));
                mapa.addMarker(marcador);
            }
        }
        dao.close();

        new Localizador(getContext(), MapaFragment.this);
    }

    private LatLng pegaCoordenadaDoEndereco(String endereco) {

        try{
            Geocoder geocoder = new Geocoder(getContext());
            List<Address> resultados = geocoder.getFromLocationName(endereco, 1);

            if(!resultados.isEmpty()){
                LatLng posicao = new LatLng(resultados.get(0).getLatitude(),
                        resultados.get(0).getLongitude());
                return posicao;
            }

        }catch(IOException e){
            e.printStackTrace();
        }
        return null;
    }

    public void centralizaEm(LatLng coordenada){
        if(mapa != null){
            CameraUpdate update = CameraUpdateFactory.newLatLngZoom(coordenada, 17);
            mapa.moveCamera(update);
        }
    }
}

package br.com.alura.agenda;

import android.content.Context;
import android.location.Location;
import android.os.Bundle;
import android.support.annotation.Nullable;

import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;

import com.google.android.gms.maps.model.LatLng;

/**
 * Created by Rodrigo on 27/03/2017.
 */

public class Localizador implements GoogleApiClient.ConnectionCallbacks, LocationListener {

    private final GoogleApiClient client;
    private final MapaFragment mapaFragment;

    public Localizador(Context context, MapaFragment mapaFragment) {
        client = new GoogleApiClient.Builder(context)
                .addApi(LocationServices.API)
                .addConnectionCallbacks(this)
                .build();

        client.connect();

        this.mapaFragment = mapaFragment;
    }

    @Override
    public void onConnected(@Nullable Bundle bundle) {

        LocationRequest request = new LocationRequest();
        request.setSmallestDisplacement(50);
        request.setInterval(1000);
        request.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);

        LocationServices.FusedLocationApi.requestLocationUpdates(client, request, this);
    }

    @Override
    public void onConnectionSuspended(int i) {

    }

    @Override
    public void onLocationChanged(Location location) {

        LatLng coordenada = new LatLng(location.getLatitude(), location.getLongitude());
        mapaFragment.centralizaEm(coordenada);
    }
}

Olhei nos outros tópicos, mas não consegui achar o problema.