https://bugs.webkit.org/show_bug.cgi?id=126382

Reviewed by Andreas Kling.

Remove PlaceholderDocument class and replace it with a bit in Document.

* WebCore.xcodeproj/project.pbxproj:
* dom/Document.cpp:
(WebCore::Document::Document):
(WebCore::Document::createRenderTree):
* dom/Document.h:
        
    Also make Synthesized a construction flag instead of a boolean parameter.

(WebCore::Document::createNonRenderedPlaceholder):
* html/HTMLDocument.cpp:
(WebCore::HTMLDocument::HTMLDocument):
* html/HTMLDocument.h:
(WebCore::HTMLDocument::create):
(WebCore::HTMLDocument::createSynthesizedDocument):
* loader/DocumentWriter.cpp:
(WebCore::DocumentWriter::createDocument):
* loader/PlaceholderDocument.cpp: Removed.
* loader/PlaceholderDocument.h: Removed.
* pdf/ios/PDFDocument.h:
(WebCore::PDFDocument::PDFDocument):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@161207 268f45cc-cd09-0410-ab3c-d52691b4dbfc