Fix for bug 17203, high CPU usage loading HTML5 spec.  This patch significantly improves the performance
        of CSS3 selectors.

        (1) Split the notion of being affected by positional rules into "forward" and "backward."  The "forward"
        selectors do not need to re-resolve during parsing, since children are appended on the end.  Only the
        "backward" selectors like last-child or nth-last-child have to re-resolve when a close tag is encountered.

        (2) Extend childrenChanged to specify whether the children were changed by the parser or not.  This allows
        Element::childrenChanged to know when the parser is adding children so that it can ignore those adds when
        possible.

        (3) Make sure all Elements now know whether or not their children are currently parsing.  Backwards selectors
        like last-child will always return false when children are still being parsed.  When an Element finishes
        parsing its children, finishParsingChildren() gets called and will make sure the children re-resolve properly.

        (4) Added a beginParsingChildren method and renamed finishParsing to finishedParsingChildren.

        (5) Eliminated one-off hacks that did the same thing in HTMLObjectElement and HTMLAppletElement.

        (6) Patched many incorrect implementations of finishedParsingChildren that did not properly call into their
        base class (mostly new SVG elements that got added for SVG fonts around the time this became a requirement).

        Reviewed by Eric

        * css/CSSStyleSelector.cpp:
        (WebCore::CSSStyleSelector::checkSelector):
        (WebCore::CSSStyleSelector::checkOneSelector):
        * dom/Attr.cpp:
        (WebCore::Attr::childrenChanged):
        * dom/Attr.h:
        * dom/ContainerNode.cpp:
        (WebCore::ContainerNode::addChild):
        * dom/Document.cpp:
        (WebCore::Document::childrenChanged):
        * dom/Document.h:
        * dom/Element.cpp:
        (WebCore::Element::Element):
        (WebCore::Element::recalcStyle):
        (WebCore::checkFirstChildRules):
        (WebCore::checkLastChildRules):
        (WebCore::checkEmptyRules):
        (WebCore::checkStyleRules):
        (WebCore::Element::childrenChanged):
        (WebCore::Element::finishParsingChildren):
        * dom/Element.h:
        (WebCore::Element::finishedParsingChildren):
        (WebCore::Element::beginParsingChildren):
        * dom/Node.cpp:
        * dom/Node.h:
        (WebCore::Node::finishParsingChildren):
        (WebCore::Node::beginParsingChildren):
        (WebCore::Node::childrenChanged):
        * dom/StyledElement.cpp:
        (WebCore::StyledElement::StyledElement):
        * dom/StyledElement.h:
        * dom/XMLTokenizer.cpp:
        (WebCore::XMLTokenizer::startElementNs):
        (WebCore::XMLTokenizer::endElementNs):
        (WebCore::):
        * html/HTMLAppletElement.cpp:
        (WebCore::HTMLAppletElement::HTMLAppletElement):
        (WebCore::HTMLAppletElement::finishParsingChildren):
        * html/HTMLAppletElement.h:
        * html/HTMLElementFactory.cpp:
        (WebCore::objectConstructor):
        * html/HTMLGenericFormElement.cpp:
        (WebCore::HTMLFormControlElementWithState::finishParsingChildren):
        * html/HTMLGenericFormElement.h:
        * html/HTMLObjectElement.cpp:
        (WebCore::HTMLObjectElement::HTMLObjectElement):
        (WebCore::HTMLObjectElement::finishParsingChildren):
        (WebCore::HTMLObjectElement::childrenChanged):
        * html/HTMLObjectElement.h:
        * html/HTMLOptGroupElement.cpp:
        (WebCore::HTMLOptGroupElement::childrenChanged):
        * html/HTMLOptGroupElement.h:
        * html/HTMLOptionElement.cpp:
        (WebCore::HTMLOptionElement::childrenChanged):
        * html/HTMLOptionElement.h:
        * html/HTMLParser.cpp:
        (WebCore::HTMLParser::insertNode):
        (WebCore::HTMLParser::pushBlock):
        (WebCore::HTMLParser::popOneBlockCommon):
        * html/HTMLScriptElement.cpp:
        (WebCore::HTMLScriptElement::childrenChanged):
        (WebCore::HTMLScriptElement::finishParsingChildren):
        * html/HTMLScriptElement.h:
        * html/HTMLSelectElement.cpp:
        (WebCore::HTMLSelectElement::childrenChanged):
        * html/HTMLSelectElement.h:
        * html/HTMLStyleElement.cpp:
        (WebCore::HTMLStyleElement::finishParsingChildren):
        (WebCore::HTMLStyleElement::childrenChanged):
        * html/HTMLStyleElement.h:
        * html/HTMLTextAreaElement.cpp:
        (WebCore::HTMLTextAreaElement::childrenChanged):
        * html/HTMLTextAreaElement.h:
        * html/HTMLTitleElement.cpp:
        (WebCore::HTMLTitleElement::childrenChanged):
        * html/HTMLTitleElement.h:
         * rendering/RenderApplet.cpp:
        (WebCore::RenderApplet::createWidgetIfNecessary):
        * rendering/RenderPartObject.cpp:
        (WebCore::RenderPartObject::updateWidget):
        * rendering/RenderStyle.cpp:
        (WebCore::RenderStyle::RenderStyle):
        * rendering/RenderStyle.h:
        (WebCore::RenderStyle::childrenAffectedByForwardPositionalRules):
        (WebCore::RenderStyle::setChildrenAffectedByForwardPositionalRules):
        (WebCore::RenderStyle::childrenAffectedByBackwardPositionalRules):
        (WebCore::RenderStyle::setChildrenAffectedByBackwardPositionalRules):
        * svg/SVGAnimationElement.cpp:
        (WebCore::SVGAnimationElement::finishParsingChildren):
        * svg/SVGAnimationElement.h:
        * svg/SVGClipPathElement.cpp:
        (WebCore::SVGClipPathElement::childrenChanged):
        * svg/SVGClipPathElement.h:
        * svg/SVGDefinitionSrcElement.cpp:
        (WebCore::SVGDefinitionSrcElement::childrenChanged):
        * svg/SVGDefinitionSrcElement.h:
        * svg/SVGElement.cpp:
        (WebCore::SVGElement::finishParsingChildren):
        * svg/SVGElement.h:
        * svg/SVGFontFaceElement.cpp:
        (WebCore::SVGFontFaceElement::childrenChanged):
        * svg/SVGFontFaceElement.h:
        * svg/SVGFontFaceFormatElement.cpp:
        (WebCore::SVGFontFaceFormatElement::childrenChanged):
        * svg/SVGFontFaceFormatElement.h:
        * svg/SVGFontFaceSrcElement.cpp:
        (WebCore::SVGFontFaceSrcElement::childrenChanged):
        * svg/SVGFontFaceSrcElement.h:
        * svg/SVGFontFaceUriElement.cpp:
        (WebCore::SVGFontFaceUriElement::childrenChanged):
        * svg/SVGFontFaceUriElement.h:
        * svg/SVGGElement.cpp:
        (WebCore::SVGGElement::childrenChanged):
        * svg/SVGGElement.h:
        * svg/SVGGradientElement.cpp:
        (WebCore::SVGGradientElement::childrenChanged):
        * svg/SVGGradientElement.h:
        * svg/SVGMarkerElement.cpp:
        (WebCore::SVGMarkerElement::childrenChanged):
        * svg/SVGMarkerElement.h:
        * svg/SVGMaskElement.cpp:
        (WebCore::SVGMaskElement::childrenChanged):
        * svg/SVGMaskElement.h:
        * svg/SVGPatternElement.cpp:
        (WebCore::SVGPatternElement::childrenChanged):
        * svg/SVGPatternElement.h:
        * svg/SVGStyleElement.cpp:
        (WebCore::SVGStyleElement::finishParsingChildren):
        (WebCore::SVGStyleElement::childrenChanged):
        * svg/SVGStyleElement.h:
        * svg/SVGStyledElement.cpp:
        (WebCore::SVGStyledElement::childrenChanged):
        * svg/SVGStyledElement.h:
        * svg/SVGTitleElement.cpp:
        (WebCore::SVGTitleElement::childrenChanged):
        * svg/SVGTitleElement.h:
        * svg/SVGUseElement.cpp:
        (WebCore::SVGUseElement::childrenChanged):
        * svg/SVGUseElement.h:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@30112 268f45cc-cd09-0410-ab3c-d52691b4dbfc