Potential use-after-free of Frame
https://bugs.webkit.org/show_bug.cgi?id=115774

Reviewed by Simon Fraser.

Merge https://chromium.googlesource.com/chromium/blink/+/c5b4a6db82e8280c7fc55ee3dc3a84c6b026e66e.

* page/Frame.cpp:
(WebCore::Frame::setPrinting):
(WebCore::Frame::setPageAndTextZoomFactors):
(WebCore::Frame::deviceOrPageScaleFactorChanged):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@149780 268f45cc-cd09-0410-ab3c-d52691b4dbfc