Add assert that updateLayoutTree clears dirty bits.

Source/core/dom/Node.h

Index: Source/core/dom/Node.h
diff --git a/Source/core/dom/Node.h b/Source/core/dom/Node.h
index 63b3599828d035b1541d653dbf0829ba1841540f..9501b4b837bb5a756868bddff05d47dd58c11897 100644
--- a/Source/core/dom/Node.h
+++ b/Source/core/dom/Node.h
@@ -739,7 +739,7 @@ private:
         HasEventTargetDataFlag = 1 << 26,
         AlreadySpellCheckedFlag = 1 << 27,
 
-        DefaultNodeFlags = IsFinishedParsingChildrenFlag | ChildNeedsStyleRecalcFlag | NeedsReattachStyleChange
+        DefaultNodeFlags = IsFinishedParsingChildrenFlag | NeedsReattachStyleChange
     };
 
     // 3 bits remaining.
@@ -753,7 +753,7 @@ protected:
     enum ConstructionType {
         CreateOther = DefaultNodeFlags,
         CreateText = DefaultNodeFlags | IsTextFlag,
-        CreateContainer = DefaultNodeFlags | IsContainerFlag,
+        CreateContainer = DefaultNodeFlags | ChildNeedsStyleRecalcFlag | IsContainerFlag,
         CreateElement = CreateContainer | IsElementFlag,
         CreateShadowRoot = CreateContainer | IsDocumentFragmentFlag | IsInShadowTreeFlag,
         CreateDocumentFragment = CreateContainer | IsDocumentFragmentFlag,