Also, apple only allows using the UIWebView, so Chrome for iOS is just safari's engine with a better interface: https://developer.chrome.com/multidevice/ios/overview And in previous iOS releases, the UIWebView had a significantly worse performance than safari: http://daringfireball.net/2011/03/nitro_ios_43

Both cases are explained as security measures. But they are coincidentally degrading web applications' performance, which benefits Apple's app store revenue.