[Mac] Playback target clients do not unregister on page reload
https://bugs.webkit.org/show_bug.cgi?id=144761
Reviewed by Brady Eidson.
* dom/Document.cpp:
(WebCore::Document::prepareForDestruction): Unregister all target picker clients.
* html/HTMLMediaElement.cpp:
(WebCore::HTMLMediaElement::registerWithDocument): Register for page cache callback.
(WebCore::HTMLMediaElement::unregisterWithDocument): Unregister for page cache callback.
(WebCore::HTMLMediaElement::documentWillSuspendForPageCache): New.
(WebCore::HTMLMediaElement::documentDidResumeFromPageCache): New.
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@184001
268f45cc-cd09-0410-ab3c-
d52691b4dbfc