Reviewed by Anders Carlsson.

        When loading a custom view into a frame, the old document is still
        around
        <rdar://problem/5145841>

        Safari fires onload before PDF is loaded into the browser
        <rdar://problem/6618869>

        Test: fast/loader/non-html-load-event.html

        * GNUmakefile.am: Added PlaceholderDocument.{cpp,h}
        * WebCore.gypi: Ditto.
        * WebCore.pro: Ditto.
        * WebCore.vcproj/WebCore.vcproj: Ditto.
        * WebCore.xcodeproj/project.pbxproj: Ditto.
        * WebCoreSources.bkl: Ditto.
        * dom/Document.h:
        (WebCore::Document::setStyleSelector): Added this protected accessor for
            PlaceholderDocument to use.
        * dom/Element.cpp:
        (WebCore::Element::clientWidth): Check whether the document has a
            renderer.
        (WebCore::Element::clientHeight): Ditto.
        * loader/FrameLoader.cpp:
        (WebCore::FrameLoader::begin): Create a PlaceholderDocument for frames
            that do not use an HTML view. Do not nullify the content size in
            that case.
        (WebCore::FrameLoader::transitionToCommitted): For frames that do not
            use an HTML view, call receivedFirstData(), which sets up the
            frame with a new PlaceHolderDocument.
        * loader/PlaceholderDocument.cpp: Added.
        (WebCore::PlaceholderDocument::attach): Sets up the style selector but
            does not create a RenderView.
        * loader/PlaceholderDocument.h: Added.
        (WebCore::PlaceholderDocument::create):
        (WebCore::PlaceholderDocument::PlaceholderDocument):

LayoutTests:

        Reviewed by Anders Carlsson.

        Safari fires onload before PDF is loaded into the browser
        <rdar://problem/6618869>

        * fast/loader/non-html-load-event-expected.txt: Added.
        * fast/loader/non-html-load-event.html: Added.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@46136 268f45cc-cd09-0410-ab3c-d52691b4dbfc