Reviewed by Eric Seidel.

        Factor HTMLConstructionSite out of HTMLTreeBuilder
        https://bugs.webkit.org/show_bug.cgi?id=41716

        The HTMLContructionSite is the model object on which the
        HTMLTreeBuilder (a controller) acts.

        No behavior change.  I'll move this class into its own file in a
        followup patch.

        * html/HTMLFormattingElementList.h:
        (WebCore::HTMLFormattingElementList::at):
        * html/HTMLTreeBuilder.cpp:
        (WebCore::HTMLTreeBuilder::HTMLTreeBuilder):
        (WebCore::HTMLConstructionSite::HTMLConstructionSite):
        (WebCore::HTMLTreeBuilder::passTokenToLegacyParser):
        (WebCore::HTMLTreeBuilder::processDoctypeToken):
        (WebCore::HTMLConstructionSite::insertHTMLHtmlStartTagBeforeHTML):
        (WebCore::HTMLConstructionSite::mergeAttributesFromTokenIntoElement):
        (WebCore::HTMLConstructionSite::insertHTMLHtmlStartTagInBody):
        (WebCore::HTMLConstructionSite::insertHTMLBodyStartTagInBody):
        (WebCore::HTMLTreeBuilder::processFakePEndTagIfPInScope):
        (WebCore::HTMLTreeBuilder::processIsindexStartTagForInBody):
        (WebCore::HTMLTreeBuilder::processStartTagForInBody):
        (WebCore::HTMLTreeBuilder::processColgroupEndTagForInColumnGroup):
        (WebCore::HTMLTreeBuilder::closeTheCell):
        (WebCore::HTMLTreeBuilder::processStartTagForInTable):
        (WebCore::HTMLTreeBuilder::processStartTag):
        (WebCore::HTMLTreeBuilder::processBodyEndTagForInBody):
        (WebCore::HTMLTreeBuilder::processAnyOtherEndTagForInBody):
        (WebCore::HTMLTreeBuilder::furthestBlockForFormattingElement):
        (WebCore::HTMLTreeBuilder::findFosterParentFor):
        (WebCore::HTMLTreeBuilder::callTheAdoptionAgency):
        (WebCore::HTMLTreeBuilder::resetInsertionModeAppropriately):
        (WebCore::HTMLTreeBuilder::processEndTagForInBody):
        (WebCore::HTMLTreeBuilder::processCaptionEndTagForInCaption):
        (WebCore::HTMLTreeBuilder::processTrEndTagForInRow):
        (WebCore::HTMLTreeBuilder::processEndTagForInTable):
        (WebCore::HTMLTreeBuilder::processEndTag):
        (WebCore::HTMLTreeBuilder::processComment):
        (WebCore::HTMLTreeBuilder::processCharacter):
        (WebCore::HTMLTreeBuilder::processEndOfFile):
        (WebCore::HTMLTreeBuilder::processDefaultForBeforeHTMLMode):
        (WebCore::HTMLTreeBuilder::processStartTagForInHead):
        (WebCore::HTMLConstructionSite::insertDoctype):
        (WebCore::HTMLConstructionSite::insertComment):
        (WebCore::HTMLConstructionSite::insertCommentOnDocument):
        (WebCore::HTMLConstructionSite::insertCommentOnHTMLHtmlElement):
        (WebCore::HTMLConstructionSite::createElementAndAttachToCurrent):
        (WebCore::HTMLConstructionSite::insertHTMLHtmlElement):
        (WebCore::HTMLConstructionSite::insertHTMLHeadElement):
        (WebCore::HTMLConstructionSite::insertHTMLBodyElement):
        (WebCore::HTMLConstructionSite::insertElement):
        (WebCore::HTMLConstructionSite::insertSelfClosingElement):
        (WebCore::HTMLConstructionSite::insertFormattingElement):
        (WebCore::HTMLTreeBuilder::processGenericRCDATAStartTag):
        (WebCore::HTMLTreeBuilder::processGenericRawTextStartTag):
        (WebCore::HTMLConstructionSite::insertScriptElement):
        (WebCore::HTMLTreeBuilder::processScriptStartTag):
        (WebCore::HTMLConstructionSite::insertTextNode):
        (WebCore::HTMLConstructionSite::createElement):
        (WebCore::HTMLTreeBuilder::indexOfFirstUnopenFormattingElement):
        (WebCore::HTMLTreeBuilder::reconstructTheActiveFormattingElements):
        (WebCore::HTMLTreeBuilder::generateImpliedEndTagsWithExclusion):
        (WebCore::HTMLTreeBuilder::generateImpliedEndTags):
        * html/HTMLTreeBuilder.h:
        (WebCore::HTMLConstructionSite::currentElement):
        (WebCore::HTMLConstructionSite::openElements):
        (WebCore::HTMLConstructionSite::activeFormattingElements):
        (WebCore::HTMLConstructionSite::head):
        (WebCore::HTMLConstructionSite::form):
        (WebCore::HTMLConstructionSite::releaseForm):
        (WebCore::HTMLConstructionSite::setForm):
        (WebCore::HTMLConstructionSite::fragmentScriptingPermission):
        (WebCore::HTMLConstructionSite::attach):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@62599 268f45cc-cd09-0410-ab3c-d52691b4dbfc