Fix bug 312563: remove a hack in the Cocoa widget code that did a synchronous invalidate on widgets when they get hidden (e.g. by tab switch) in order to promptly notify plugins that their visibility is changing. This caused problems on some sites, because forcing the NSView to display when the view hierarchy is in flux could leave the window in a non-drawing state. r=mento.
git-svn-id: svn://10.0.0.236/branches/MOZILLA_1_8_BRANCH@182784 18797224-902f-48f8-a5cc-f745e15eee43
6b562dd49c