Apple has decided to stop hogging some of the performance it once reserved for Safari on iOS.
"Over the years we've seen a lot of requests from all of you for something a bit more powerful," Carlsson said in his WWDC talk. Apple therefore created a new programming interface called WKWebView for both iOS and OS X to tap into WebKit.
Ordinary folks will benefit. Many apps draw on Web technology, and they should run faster or get more features as programmers take advantage of new performance.
The biggest beneficiaries will be third-party browsers, though, most notably Google's Chrome. On Android, Windows, Linux, and OS X, Chrome uses Google's Blink browser engine, which was diverged from WebKit in 2013. But on iOS, Google has to use Apple's WebKit.
But Apple wouldn't let the third-party software use that JIT compiler. One possible reason was security: a JIT compiler essentially creates a new program on the fly and marks the region of memory it's stored in as executable, and a hacker could potentially abuse that privilege. Apparently Apple is satisfied that its approach is secure enough though. The loosened restriction also matches what Google does with Android's built-in browser technology, so competitive considerations could be involved, too.
Other aspects drawn from Safari include "supersmooth 60-frames-per-second scrolling using hardware acceleration and CoreAnimation," Carlsson said.
And there's more: "We've taken the back/forward swipes and the pinch-to-zoom gestures from Safari and built them right into WebKit," he told developers. Another feature is "a really cool way for your app to talk to Web pages and vice versa."
reading•iOS 8 grants new power to rival browsers, Web-based apps
Sep 18•iOS 12: Do Not Disturb and Notifications get major overhauls
Sep 17•iOS 12: What to know about Siri's new Shortcuts feature
Sep 17•How to use iOS 12's fun new Memoji feature
Sep 17•iOS 12: Getting to know Screen Time and stronger parental controls