Reviewed by Adam.

    Reviewed by Adam.

        - fixed layout test failure in fast/overflow/scrollRevealButton

        I added a new ScrollView method, fullyClippedContentRect, that vies the content rect
        as clipped by all ancestor scroll views, not just this one. Currently it only works
        correctly on mac however. visibleContentRect, only accounting for the clipping from
        this particular scroll view, is sufficient for most purposes.

        * page/Frame.cpp:
        (WebCore::Frame::visibleSelectionRect):
        (WebCore::Frame::setIsActive):
        (WebCore::Frame::markAllMatchesForText):
        * platform/ScrollView.h:
        * platform/gdk/ScrollViewGdk.cpp:
        (WebCore::ScrolView::fullyClippedContentRect):
        * platform/mac/ScrollViewMac.mm:
        (WebCore::ScrollView::fullyClippedContentRect):
        * platform/qt/ScrollViewQt.cpp:
        (WebCore::ScrolView::fullyClippedContentRect):
        * rendering/RenderLayer.cpp:
        (WebCore::RenderLayer::scrollRectToVisible):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@19846 268f45cc-cd09-0410-ab3c-d52691b4dbfc