No browser screen shown up with WAM and Browser App with chromium68

  * Chromium68:   https://github.com/webosose/chromium68 (branch: @15.agl.flounder)
  * WAM:          https://github.com/webosose/wam (branch @2.chromium68.5.agl.flounder)
  * meta-agl-lge: https://github.com/webosose/meta-agl-lge (branch flounder.chromium68)

With the current recipe with chromium68, we can't see the screen updated from WAM and Browser App.