WebKit rendering engine has been used by Chromium since the start of the project, but Chromium uses a different multi-process architecture than other WebKit-based browsers, and this has made maintenance increasingly complex, and Google intends to investigate other performance improvement strategies. Those 2 reasons explain why the company has announced it would fork WebKit and start working on its own open source rendering engine called Blink.
Google tells web developers that in the short term, Blink will bring little change to them, as most of the work will focus on architectural improvements as well as code cleanup with about 7,000 files, corresponding to 4.5 millions line of code, to be deleted.
One of the main changes will be “out-of-process iframes“, where the rendering engine will start a sandbox process for each individual parts of the page in order to render it faster. This has been planned for a while, but since implementing it in WebKit would have broken other people implementation it had been delayed.
Opera recently announced it would be switching to WebKit, but Bruce Lawson, an Opera employee, confirmed it will actually use Blink. Hopefully, Blink will only bring positive for a faster and more secure web browsing experience, and there won’t be too much extra work (ideally none) to make sure websites still work properly with Blink.
Update: Google has uploaded a 30 minutes video answering the most popular developers questions about Blink.