WebKit: use-after-free in WebCore::Style::TreeResolver::styleForElement(CVE-2017-13802)

There is a use-after-free security vulnerability in WebKit. The vulnerability was confirmed on ASan build of WebKit nightly. ASan log: ================================================================= ==30588==ERROR: AddressSanitizer: heap-use-after-free on address 0x608000077ec8 at pc...