What is CRiOS and OPiOS?

Recently i have been seeing this as web browser in the web tracker. It looks like it is chrome browser version of IOS and Opera browser verison for IOS. It seems if one does

if (Request.UserAgent != null && Request.UserAgent.IndexOf("crios",StringComparison.OrdinalIgnoreCase) > -1)
{
    this.ClientTarget = "uplevel";
}

to check on the chrome version of IOS and hopefully same may apply for the other browser as it comes with that as the file name

OPiOS/9.2.0.88656 was an Opera Mini for iOS Update
Release date: Tue., 03. Feb. 2015
Source: http://blogs.opera.com/mobile/2015/02/drag-open-new-tabs-search-better-opera-mini-9-2-ios/