Everything you said in your opening paragraph above has already been said before.
Thomas Thomassen has a WebDialog manual online:
Many over the years. Some in old forums that have long since been archived and are no longer available. (SketchUp has been owned by 3 companies, and the first two owners went through a couple of different forum sites. I think this site may be at least the fifth official SketchUp forum.)
You’ll find quite a few discussions about the
UI::WebDialog class over at the SketchUcation Developers forum, going back more than 8 years.
As a publicly traded company, Trimble employees cannot make any “forward looking statements” nor divulge future product plans. That is marketing’s job. Historically, the “plans” are never revealed until the public release, and they usually happen along with some fanfare / event like Trimble Horizons, or 3D BaseCamp.
I myself played around and tested running ChromeFrame inside a MSIE SketchUp WebDialog, and it worked,… BUT,… it required that security was switched off machine-wide, which was an unacceptable risk. So that avenue died, quickly. I even discussed fixing this issue with the Google developers in CA, but they were not interested in tweaking the public build for embedded use, and basically said we need to tweak and build our own edition of Chromium. I looked into it and it is way too complicated unless you already know *nix like systems and GNU tools. Way beyond me.
At one time, I was suggesting perhaps an API wrapper around Gecko. (I think,… it was a long while ago.)
Anyway, since those times, Thomas Thomassen has written some wrappers around the Webdialog using the JQuery framework.