<https://webkit.org/b/120304>

Reviewed by Darin Adler.

Let's enforce this better by storing a RenderView* instead of a plain RenderObject*.
We should switch callers that grab at Document::renderer() to calling renderView()
instead, but that's better done separately.

* dom/Document.cpp:
(WebCore::Document::Document):
(WebCore::Document::~Document):
(WebCore::Document::setRenderView):
(WebCore::Document::createRenderTree):
(WebCore::Document::detach):
(WebCore::Document::setInPageCache):
* dom/Document.h:
(WebCore::Document::renderView):
(WebCore::Document::renderer):
* html/parser/HTMLResourcePreloader.cpp:
* rendering/RenderObject.cpp:
(WebCore::RenderObject::setStyle):
* rendering/RenderView.h:
* svg/SVGSVGElement.cpp:
(WebCore::SVGSVGElement::updateCurrentTranslate):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@154676 268f45cc-cd09-0410-ab3c-d52691b4dbfc