Actually, as a tidbit, Chromium is a fork of WebKit, which is Safari's rendering engine, which for some reason started as a fork from Konqueror (KDE Linux desktop's browser).
Google did however replace the javascript engine in Chromium.
The Javascript engine in Chromium deserves a different discussion, since it also powers NodeJS.
Back in the day, WebKit was quite popular as a rendering engine and is also used by Qt.
Ken Kocienda writes about the origin of Safari in Creative Selection [0].
It started as a Konqueror fork mostly because Jobs wanted a browser on OS X and Ken was initially tasked with it (back then the mac had IE for mac). One person writing a browser from scratch even back then seemed an impossible challenge so he took a look to see if he could use most of Konqueror as an initial starting base.
[0]: The book has some interesting stories, but I find it hard to recommend because it's weirdly written for an extremely non-technical audience (using grandma like analogies to explain basic concepts, the analogies are so basic they do more to obscure than explain - e.g. the filesystem is like a 'cabinet for files'). It doesn't often get into the weeds of the interesting technical details - which is disappointing since 90% of readers are probably technical. The stories in it are still good though and Ken has a lot of insight into the iPhone development story since he was there.
Minor correction: Ken Kocienda didn't do the Konqueror port. He was working on getting Gecko to build and a teammate got Konqueror working in X11 before Ken even got Gecko to compile.
KHTML was a pretty viable alternative to the mess that was Gecko at the time. And there were already some (underserved) alternative platform ports in-progress at the time.
It started as a fork of Konqueror because it was the highest-quality codebase available, probably because it was open-source from the ground up and written in a higher-level language rather than the l33t h4x0rs at Netscape with their 4 different memory allocators.
