Make classes and structures in core/html fast-allocated.

Source/core/html/parser/HTMLConstructionSite.h

Index: Source/core/html/parser/HTMLConstructionSite.h
diff --git a/Source/core/html/parser/HTMLConstructionSite.h b/Source/core/html/parser/HTMLConstructionSite.h
index b039ef1eeaf1feba8bfc83a0029c6dcc1abe6e43..8e2b3d14e873375fb96e03a7b154235245b1e28b 100644
--- a/Source/core/html/parser/HTMLConstructionSite.h
+++ b/Source/core/html/parser/HTMLConstructionSite.h
@@ -202,6 +202,7 @@ public:
     ParserContentPolicy parserContentPolicy() { return m_parserContentPolicy; }
 
     class RedirectToFosterParentGuard {
+        STACK_ALLOCATED();
         WTF_MAKE_NONCOPYABLE(RedirectToFosterParentGuard);
     public:
         RedirectToFosterParentGuard(HTMLConstructionSite& tree)