If I’m reading this post correctly, when you install Google Chrome on your iOS device you are not getting Google’s preferred rendering engine, instead you are still getting Apple’s. So effectively, Google Chrome on iOS is just a skin on top of Safari.
Due to constraints of the iOS platform, all browsers must be built on top of the WebKit rendering engine. For Chromium, this means supporting both WebKit as well as Blink, Chrome’s rendering engine for other platforms. That created some extra complexities which we wanted to avoid placing in the Chromium code base.