WebKit actually has multiple different API layers. There is the Cocoa API used by Safari on Mac, a Gtk API, a Qt API, and a special API just for Chrome. WebKit2

WebKit actually has multiple different API layers. There is the Cocoa API used by Safari on Mac, a Gtk API, a Qt API, and a special API just for Chrome. WebKit2 is really a peer to all these APIs, although we also hope it can be a tool for building new tightly integrated APIs that support multiprocess and nonblocking operation. The bottom line is that Chrome and Safari will not be sharing any less WebKit code than before - the WebCore layer, the part that does most of the heavy lifting in rendering Web content - remains unchanged. We may actually have the opportunity to share more code since we'll now be facing many of the same problems. We also hope the Chrome team someday decides to go more in a WebKit2 direction and do multiprocess inside the WebKit API boundary instead of outside, so they can share more code with other port. But that's up to them, and they already have a lot invested in their current path.