Reviewed by Dimitri Glazkov.

        Bug 52963 - Enable O(1) access to root from any node in shadow DOM subtree
        https://bugs.webkit.org/show_bug.cgi?id=52963

        .) Change base class of ShadowRoot from DocumentFragment to TreeScope.
        .) Re-enable tree scope handling in Node (had ASSERT_NOT_REACHED, etc.).
        .) Merged setTreeScope() with setTreeScopeRecursively()
        .) Call setTreeScopeRecursively in DOM manipulation functions where applicable.
        .) Adapt JavaScript Node wrappers (temporary code - see https://bugs.webkit.org/show_bug.cgi?id=58704).

        No new tests. (refactoring)

        * bindings/js/JSNodeCustom.cpp:
        (WebCore::createWrapperInline):
        * bindings/v8/custom/V8NodeCustom.cpp:
        (WebCore::toV8Slow):
        * dom/ContainerNode.cpp:
        (WebCore::ContainerNode::takeAllChildrenFrom):
        (WebCore::ContainerNode::removeBetween):
        (WebCore::ContainerNode::removeChildren):
        (WebCore::ContainerNode::parserAddChild):
        * dom/Document.cpp:
        (WebCore::Document::Document):
        (WebCore::Document::~Document):
        (WebCore::Document::setDocType):
        * dom/Element.h:
        * dom/Node.cpp:
        (WebCore::Node::treeScope):
        (WebCore::Node::setTreeScopeRecursively):
        * dom/Node.h:
        (WebCore::Node::document):
        * dom/ShadowRoot.cpp:
        (WebCore::ShadowRoot::ShadowRoot):
        (WebCore::ShadowRoot::~ShadowRoot):
        (WebCore::ShadowRoot::nodeType):
        (WebCore::ShadowRoot::cloneNode):
        (WebCore::ShadowRoot::childTypeAllowed):
        * dom/ShadowRoot.h:
        (WebCore::toShadowRoot):
        * dom/TreeScope.cpp:
        (WebCore::TreeScope::TreeScope):
        (WebCore::TreeScope::setParentTreeScope):
        * dom/TreeScope.h:
        * rendering/RenderSlider.cpp:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@84394 268f45cc-cd09-0410-ab3c-d52691b4dbfc