I assume this is because of the new HTMLTreeBuilder, but basic HTMLDocuments contain <html>, <head>, and <body>. But they were requiring loadFullDefaultStyle because <head> is not in the simple stylesheet. It should be added, its very simple.
<rdar://problem/9240816>
Created attachment 88360 [details] [PATCH] Add head to the simpleStyleSheet.
Comment on attachment 88360 [details] [PATCH] Add head to the simpleStyleSheet. It built fine for me.
Comment on attachment 88360 [details] [PATCH] Add head to the simpleStyleSheet. r=me
Comment on attachment 88360 [details] [PATCH] Add head to the simpleStyleSheet. Clearing flags on attachment: 88360 Committed r83032: <http://trac.webkit.org/changeset/83032>
All reviewed patches have been landed. Closing bug.