Reviewed by Adam Barth.

        Put view-source documents in a unique origin and always allow them to run scripts. This ensures tools like
        XMLViewer work even when scripts are disabled, while still providing the protections expected when scripts are disabled.
        https://bugs.webkit.org/show_bug.cgi?id=59113

        * bindings/ScriptControllerBase.cpp:
        (WebCore::ScriptController::canExecuteScripts): Check whether the document is viewing source, and allow scripts in that case.
        * css/CSSStyleSelector.cpp:
        (WebCore::CSSStyleSelector::matchUARules):
        * dom/Document.cpp:
        (WebCore::Document::Document):
        (WebCore::Document::setIsViewSource): Renamed from setUsesViewSourceStyles(), set's a unique security origin if we are viewing source.
        * dom/Document.h:
        (WebCore::Document::isViewSource): Renamed from usesViewSourceStyles().
        * html/HTMLViewSourceDocument.cpp:
        (WebCore::HTMLViewSourceDocument::HTMLViewSourceDocument):
        * loader/FrameLoader.cpp:
        (WebCore::FrameLoader::receivedFirstData):
        * xml/XMLTreeViewer.cpp:
        (WebCore::XMLTreeViewer::transformDocumentToTreeView):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@87309 268f45cc-cd09-0410-ab3c-d52691b4dbfc