General observations, connected to the question but not necessarily relevant.
Since posting the above, I have found that Opera's latest release has finally caught up to Chrome in compliance with HTML5. There is an even more recent argument that suggests Chrome is going to be challenged by the recently released Firefox Quantum. As Chrome is estimated to have 60% of the market, and Firefox 8.5%, this is a pretty big call, I thought. Given that Edge and Internet Exploder at 6.5%, Opera a growing 3.4% with the Mac's Safari taking most of the rest thay are, I suspect, going to be left behind. Other offerings, like Vivaldi, take small shares, but they are mostly developing applications often for specific situations their devs meet. Yes, Chrome is out performed is some areas by these other browsers, but overall Chrome is assessed by its responsiveness and minimalist design and it still very fast. However, with the release of FF Quantum, its reduced memory consumption and its ability to better handle complex apps, may just give it the impetus it needs to claw back some of the support it has had in the past. Notice though, IE and Edge do not rate a mention here. Opera has improved but the other two haven't.