message: Got crumb from intents size
  Safe than getting it from currentActivity for things like double clicks. The second click could happen before the activity's changed from first click and so it would add the activities again.
diff: @@ -28,7 +28,7 @@ public class NavigationMotion extends ReactContextBaseJavaModule {
  if (mIntents.size() == 0) {
  mIntents.put(0, currentActivity.getIntent());
  }
  - int currentCrumb = currentActivity.getIntent().getIntExtra("crumb", 0);
  + int currentCrumb = mIntents.size() - 1;
  if (crumb < currentCrumb) {
  currentActivity.navigateUpTo(mIntents.get(crumb));
  for(int i = crumb + 1; i <= currentCrumb; i++) {
  