I think that would not happen, with all the difference and mess in implementation under multiple browsers (even with webkit based Safari and Chrome), and file watcher+auto reload is less of a headache.
It's very efficient and less headache. WebStorm could add webkit and sync the code view like Dreamweaver. JetBrain's IDE is Java based and integrating a C++ based WYSIWYG view might be more complicated. And all the Java based browsers have been discontinued like https://en.wikipedia.org/wiki/HotJava .