Manage Fragment when rotating

Activity

public class MainActivity extends AppCompatActivity {

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

        if (getFragmentManager().findFragmentById(R.id.fragment) == null) {
            getFragmentManager().beginTransaction().replace(R.id.fragment, new MainActivityFragment()).commit();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onBackPressed() {
        MainActivityFragment fragment = (MainActivityFragment) getFragmentManager().findFragmentById(R.id.fragment);
        if (fragment.webView.canGoBack()) {
            fragment.webView.goBack();
        } else {
            super.onBackPressed();
        }
    }

}

Fragment

/**
 * A placeholder fragment containing a simple view.
 */
public class MainActivityFragment extends Fragment {

    WebView webView;

    public MainActivityFragment() {
    }

    @Override
    public void onResume() {
        super.onResume();
        setRetainInstance(true);
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        webView.saveState(outState);
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        webView.restoreState(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_main, container, false);
        Log.i("fragment", "onCreateView");

        webView = (WebView) view.findViewById(R.id.webview);
        webView.setWebViewClient(new WebViewClient());

        if (savedInstanceState == null) {
            webView.loadUrl("http://www.google.com");
        }
        return view;
    }

}