Add assert that updateLayoutTree clears dirty bits.

Source/core/html/parser/HTMLConstructionSite.cpp

 /*
  * Copyright (C) 2010 Google, Inc. All Rights Reserved.
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 84 matching lines @@
 static inline bool isAllWhitespace(const String& string)
 {
     return string.isAllSpecialCharacters<isHTMLSpace<UChar>>();
 }
 
 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
         task.parent->parserAppendChild(task.child.get());
 }
 
 static inline void executeInsertTask(HTMLConstructionSiteTask& task)
 {
     ASSERT(task.operation == HTMLConstructionSiteTask::Insert);
 
@@ skipping 760 matching lines @@
 }
 
 DEFINE_TRACE(HTMLConstructionSite::PendingText)
 {
     visitor->trace(parent);
     visitor->trace(nextChild);
 }
 
 
 }