message: Copied code from ReactActivityDelegate
diff: @@ -6,6 +6,7 @@ import android.view.KeyEvent;
  import com.facebook.react.ReactApplication;
  import com.facebook.react.ReactInstanceManager;
  +import com.facebook.react.ReactNativeHost;
  import com.facebook.react.ReactRootView;
  import com.facebook.react.common.LifecycleState;
  import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;
  @@ -20,25 +21,27 @@ public class Scene extends Activity implements DefaultHardwareBackBtnHandler {
  mReactRootView = new ReactRootView(this);
  Bundle props = new Bundle();
  props.putInt("crumb", getIntent().getIntExtra("crumb", 0));
  - mReactRootView.startReactApplication(getReactInstanceManager(), "android", props);
  + mReactRootView.startReactApplication(getReactNativeHost().getReactInstanceManager(), "android", props);
  setContentView(mReactRootView);
  }
  - private ReactInstanceManager getReactInstanceManager() {
  - return ((ReactApplication) getApplication()).getReactNativeHost().getReactInstanceManager();
  +
  + private ReactNativeHost getReactNativeHost() {
  + return ((ReactApplication) getApplication()).getReactNativeHost();
  }
  +
  @Override
  protected void onPause() {
  super.onPause();
  - if (getReactInstanceManager() != null) {
  - getReactInstanceManager().onHostPause(this);
  + if (getReactNativeHost().hasInstance()) {
  + getReactNativeHost().getReactInstanceManager().onHostPause(this);
  }
  }
  @Override
  protected void onResume() {
  super.onResume();
  - if (getReactInstanceManager() != null) {
  - getReactInstanceManager().onHostResume(this, this);
  + if (getReactNativeHost().hasInstance()) {
  + getReactNativeHost().getReactInstanceManager().onHostResume(this, this);
  }
  }
  @@ -52,8 +55,8 @@ public class Scene extends Activity implements DefaultHardwareBackBtnHandler {
  @Override
  public boolean onKeyUp(int keyCode, KeyEvent event) {
  - if (keyCode == KeyEvent.KEYCODE_MENU && getReactInstanceManager() != null) {
  - getReactInstanceManager().showDevOptionsDialog();
  + if (keyCode == KeyEvent.KEYCODE_MENU && getReactNativeHost().hasInstance()) {
  + getReactNativeHost().getReactInstanceManager().showDevOptionsDialog();
  return true;
  }
  return super.onKeyUp(keyCode, event);
  @@ -61,8 +64,8 @@ public class Scene extends Activity implements DefaultHardwareBackBtnHandler {
  @Override
  public void onBackPressed() {
  - if (getReactInstanceManager() != null) {
  - getReactInstanceManager().onBackPressed();
  + if (getReactNativeHost().hasInstance()) {
  + getReactNativeHost().getReactInstanceManager().onBackPressed();
  } else {
  super.onBackPressed();
  }
  