Fixed: <rdar://problem/3886415> arrow keys don't work when the user hits Back to...

	Fixed: <rdar://problem/3886415> arrow keys don't work when the user hits Back to return to RSS page

        Reviewed by hyatt.

        (KWQKHTMLPart::openURLFromPageCache): restore mousePressNode
        (KWQKHTMLPart::mousePressNode): new
        * kwq/KWQPageState.h:
        * kwq/KWQPageState.mm:
        (-[KWQPageState initWithDocument:URL:windowProperties:locationProperties:interpreterBuiltins:]): save the mousePressNode
        (-[KWQPageState clear]): clear the mousePressNode
        (-[KWQPageState dealloc]): deref the mousePressNode
        (-[KWQPageState mousePressNode]): new

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@8380 268f45cc-cd09-0410-ab3c-d52691b4dbfc