https://bugs.webkit.org/show_bug.cgi?id=124571

Reviewed by Ryosuke Niwa.

Though there are a lot of clean up commits before, there are still
use of static_cast<HTMLFooElement*>. To clean up them, we need to generate
toHTMLDetails|Meta|Summary|TableCaptionElement().

Additionally, other static_cast<> are removed as well.

No new tests, no behavior changes.

* html/HTMLDetailsElement.h:
* html/HTMLMediaElement.cpp:
(HTMLMediaElement::selectNextSourceChild):
* html/HTMLMetaElement.h:
* html/HTMLObjectElement.cpp:
(WebCore::HTMLObjectElement::shouldAllowQuickTimeClassIdQuirk):
* html/HTMLOptionElement.cpp:
(WebCore::HTMLOptionElement::isDisabledFormControl):
* html/HTMLPlugInImageElement.cpp:
(WebCore::HTMLPlugInImageElement::updateWidgetCallback):
* html/HTMLSummaryElement.cpp:
(WebCore::HTMLSummaryElement::detailsElement):
* html/HTMLSummaryElement.h:
* html/HTMLTableCaptionElement.h:
* html/HTMLTableElement.cpp:
(WebCore::HTMLTableElement::caption):
* html/HTMLTagNames.in:
* html/MediaDocument.cpp:
(WebCore::MediaDocumentParser::createDocumentStructure):
* html/shadow/DetailsMarkerControl.cpp:
(WebCore::DetailsMarkerControl::summaryElement):
* loader/FrameLoader.cpp:
(WebCore::FrameLoader::handleFallbackContent):
* loader/ImageLoader.cpp:
(WebCore::ImageLoader::dispatchPendingBeforeLoadEvent):
* page/DragController.cpp:
(WebCore::DragController::canProcessDrag):
* page/Frame.cpp:
(WebCore::Frame::searchForLabelsBeforeElement):
* page/SpatialNavigation.cpp:
(WebCore::frameOwnerElement):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@159604 268f45cc-cd09-0410-ab3c-d52691b4dbfc