Remove Attr child nodes (making Attr a Node, not a ContainerNode)

Source/core/dom/Attribute.h

Index: Source/core/dom/Attribute.h
diff --git a/Source/core/dom/Attribute.h b/Source/core/dom/Attribute.h
index d4710aea40d2b9ce78c246d74ec23ec781a7af5e..df790ec0bc9356fe85f5a504b57e804250217c3e 100644
--- a/Source/core/dom/Attribute.h
+++ b/Source/core/dom/Attribute.h
@@ -29,9 +29,9 @@
 
 namespace blink {
 
-// This has no counterpart in DOM.
-// It is an internal representation of the node value of an Attr.
-// The actual Attr with its value as a Text child is allocated only if needed.
+// This is the internal representation of an attribute, consisting of a name and
+// value. It is distinct from the web-exposed Attr, which also knows of the
+// element to which it attached, if any.
 class Attribute {
 public:
     Attribute(const QualifiedName& name, const AtomicString& value)