Merge changes from topic 'am-9eed976f-7d63-45d0-ad0c-14ddd50e37d1' into ub-launcher3-master

* changes:
  Changes on the wallpaper gradient extraction algorithm:  fallback colors for very light or very dark luminosity. am: 97f93583d3 am: 3f97132bc1
  Changes on the wallpaper gradient extraction algorithm:  fallback colors for very light or very dark luminosity. am: 97f93583d3
  Changes on the wallpaper gradient extraction algorithm:  fallback colors for very light or very dark luminosity.