docs: public Intent getPreviewFileIntent(Context context, String path, String lastRev) {
          // TODO(jiuyangzhao): Assert path is valid
          Intent previewIntent = new Intent(ACTION_SHOW_DROPBOX_PREVIEW);
          addExtrasToIntent(context, previewIntent);
          previewIntent.putExtra(EXTRA_DROPBOX_PATH, path);
          previewIntent.putExtra(EXTRA_DROPBOX_REV, lastRev);
  
          if (getDropboxAppPackage(context, previewIntent) == null) {
              return null;
          }
          return previewIntent;
      }