Reviewed by Darin.

    Reviewed by Darin.

	- fixed <rdar://problem/4125222> Dashboard heap size grows over time (leak caused by JavaScript DOM node wrappers?)

	- changed per-document DOMObject caching to work with DOMNodes, since that is all it was used for anyway.

        Test cases added: (these tests actually ensure that DOM wrappers
	are sufficiently protected from GC to match other browsers, they
	do not verify that the leak is fixed since there's no way to test
	that with layout tests).

        * layout-tests/fast/dom/gc-1-expected.txt: Added.
        * layout-tests/fast/dom/gc-1.html: Added.
        * layout-tests/fast/dom/gc-2-expected.txt: Added.
        * layout-tests/fast/dom/gc-2.html: Added.
        * layout-tests/fast/dom/gc-3-expected.txt: Added.
        * layout-tests/fast/dom/gc-3.html: Added.

        * khtml/ecma/kjs_binding.cpp:
        (KJS::ScriptInterpreter::forgetDOMObjectForDocument): New function - allows nodes
	that get removed from the document to go away from the cache if not referenced.
        (KJS::ScriptInterpreter::mark): Don't mark nodes that aren't in the document,
	they can stay in the cache but only if they have another source of life.
        (KJS::ScriptInterpreter::domNodesPerDocument): Renamed and changed parameter types.
        (KJS::ScriptInterpreter::getDOMNodeForDocument): Renamed and changed parameter types.
        (KJS::ScriptInterpreter::forgetDOMNodeForDocument): Renamed and changed parameter types.
        (KJS::ScriptInterpreter::putDOMNodeForDocument): Renamed and changed parameter types.
        (KJS::ScriptInterpreter::forgetAllDOMNodesForDocument): Renamed and changed parameter types.
        (KJS::ScriptInterpreter::updateDOMNodeDocument): Renamed and changed parameter types.
        * khtml/ecma/kjs_binding.h:
        * khtml/ecma/kjs_dom.cpp:
        (KJS::DOMNode::~DOMNode): call forgetDOMObjectForDocument.
        (KJS::DOMNode::mark): If the node is not in the document, make sure to mark
	all wrappers in its detached piece of the tree.
        (KJS::getDOMNode): Updated for renames
        * khtml/ecma/kjs_dom.h:
        * khtml/xml/dom_docimpl.cpp:
        (DocumentImpl::~DocumentImpl): Updated for renames.
        * khtml/xml/dom_nodeimpl.cpp:
        (NodeImpl::checkAddChild): Updated for renames.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@9230 268f45cc-cd09-0410-ab3c-d52691b4dbfc