Add assert that updateLayoutTree clears dirty bits.

Source/core/html/parser/HTMLConstructionSite.cpp

Index: Source/core/html/parser/HTMLConstructionSite.cpp
diff --git a/Source/core/html/parser/HTMLConstructionSite.cpp b/Source/core/html/parser/HTMLConstructionSite.cpp
index 9046c24ed248ed9fc30274a385c96dabd1dbab5b..3de5327d44aae5d5013fcec6dccd9da7b11558cb 100644
--- a/Source/core/html/parser/HTMLConstructionSite.cpp
+++ b/Source/core/html/parser/HTMLConstructionSite.cpp
@@ -102,6 +102,12 @@ static inline void insert(HTMLConstructionSiteTask& task)
     if (isHTMLTemplateElement(*task.parent))
         task.parent = toHTMLTemplateElement(task.parent.get())->content();
 
+    if (task.parent->isDocumentNode()) {
+        Document& document = toDocument(*task.parent);
+        if (!document.canAcceptChild(*task.child, nullptr, IGNORE_EXCEPTION))
+            return;
+    }

[kouhei (in TOK), 2015/05/28 03:54:53]

This change lg tm. Would you like to split this up to separate CL for landing?

+
     if (task.nextChild)
         task.parent->parserInsertBefore(task.child.get(), *task.nextChild);
     else