HTMLConstructionSite::m_{head,form} Add reference to the HTML spec

third_party/WebKit/Source/core/html/parser/HTMLConstructionSite.h

Index: third_party/WebKit/Source/core/html/parser/HTMLConstructionSite.h
diff --git a/third_party/WebKit/Source/core/html/parser/HTMLConstructionSite.h b/third_party/WebKit/Source/core/html/parser/HTMLConstructionSite.h
index ea9952dd5ea765062b89aa149ef88e9930bcdb52..3669009af8f34df020cba43ab887126a79acb2c8 100644
--- a/third_party/WebKit/Source/core/html/parser/HTMLConstructionSite.h
+++ b/third_party/WebKit/Source/core/html/parser/HTMLConstructionSite.h
@@ -251,7 +251,9 @@ private:
     // and a Document in all other cases.
     Member<ContainerNode> m_attachmentRoot;
 
+    // https://html.spec.whatwg.org/multipage/syntax.html#head-element-pointer
     Member<HTMLStackItem> m_head;
+    // https://html.spec.whatwg.org/multipage/syntax.html#form-element-pointer
     Member<HTMLFormElement> m_form;
     mutable HTMLElementStack m_openElements;
     mutable HTMLFormattingElementList m_activeFormattingElements;