Some question about "life of a navigation(chrome university 2018& 2019)"

[18楼梦想改造家]

Hey, I start learn the chrome navigation part. And I learn it from this slide( Life of a Navigation (public) - 2018-06 - Google 幻灯片  ).

And I learn it from the two videos:

1. Chrome University 2018: Life of a Navigation - YouTube

2. Life of a navigation (Chrome University 2019) - YouTube

After read this, something makes me confusion. But I don't find the slide author's emal... So I think this a good place to ask the question.

The first question is(see picuture 00):

>  The original has said: "If over process limit, reuse compatible/suitable processes". So if we have navigate from a.com/a.html to a.com/b.html in "same tab". It will share same SiteInstance. And If we a.com/a.html, and in "another tab", we navigate to a.com/b.html, it can't share same siteinstance(One is blue, one is green). And again, If over the process limit, we try to resue compatible/suitable processes. So again, we found a.com/a.html and a.com/b.html is compatible. we try to merge their siteinstance. even if they are in differenct tabs. Does I understand this correctly?

2. The second question is(see picture 01):

In the video(24:20), the author mentioned there are a optimization named speculative renderframehost. I know it is for deal with slow netwrok process. But What it is, How it been implment? 

Thank u very much!