Google has announced that now chrome code for iOS will be a part of chromium open source project. Because Apple has constraints so Chrome has to use WebKit rendering engine instead of using Google’s own Blink engine. For chromium, supporting both the rendering engines will add up more complexities.
After spending several years in upstreaming the code for chrome for iOS into Chromium. Google is finally ready and developers are invited to compile the iOS version of Chromium.
As per the official chromium blog, development speed will also increase because the tests which developers will run on chromium will also run automatically on the chrome for iOS code base.Source: Chromium Blog