Don't sort tree scopes in StyleEngine.

sky/engine/core/dom/StyleEngine.h

Index: sky/engine/core/dom/StyleEngine.h
diff --git a/sky/engine/core/dom/StyleEngine.h b/sky/engine/core/dom/StyleEngine.h
index 9be10a3fe4082125e91671493b8d0ebbbdf867a4..9d8e89114fbaaa68e90abd9d3a83dd70fa4338cf 100644
--- a/sky/engine/core/dom/StyleEngine.h
+++ b/sky/engine/core/dom/StyleEngine.h
@@ -134,9 +134,6 @@ private:
 
     void markTreeScopeDirty(TreeScope&);
 
-    typedef ListHashSet<TreeScope*, 16> TreeScopeSet;
-    static void insertTreeScopeInDocumentOrder(TreeScopeSet&, TreeScope*);
-
     void createResolver();
 
     const StyleSheetCollection* documentStyleSheetCollection() const
@@ -159,6 +156,7 @@ private:
     typedef HashSet<RawPtr<const ScopedStyleResolver> > ScopedStyleResolverSet;
     ScopedStyleResolverSet m_scopedStyleResolvers;
 
+    typedef ListHashSet<TreeScope*, 16> TreeScopeSet;
     TreeScopeSet m_dirtyTreeScopes;
     TreeScopeSet m_activeTreeScopes;