You mean the way Google piggy-packed on Apples work which in turn piggy-backed on KDEs work? Amazon did an extension to optimise rendering on small devices, which is complexity wise not too far off to what Apple & Google contributed to the rendering engines, which at the end is the tricky bit an a browser, not the Chrome.
Really don't understand the downvotes. Whether they gave back to the community or not is another story, but they did piggy-back on previous code, even though adding a lot themselves and giving back a lot, but it still built on massive existing work.