Fix a bug that document.importNode() doesn't clone Attr nodes with namespace.

We should just call Attr::Clone().

Bug: 812089, 812105
Change-Id: I163769e134a52d82b88834ae29083a01a3480e95
Reviewed-on: https://chromium-review.googlesource.com/925865Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537730}

third_party/WebKit/LayoutTests/external/wpt/dom/nodes/Document-importNode.html

@@ -54,4 +54,14 @@ test(function() {
   assert_equals(newDiv.ownerDocument, document);
   assert_equals(newDiv.firstChild, null);
 }, "False 'deep' argument.")
+
+test(function() {
+  let doc = document.implementation.createHTMLDocument("Title");
+  doc.body.setAttributeNS("http://example.com/", "p:name", "value");
+  let originalAttr = doc.body.getAttributeNodeNS("http://example.com/", "name");
+  let imported = document.importNode(originalAttr, true);
+  assert_equals(imported.prefix, originalAttr.prefix);
+  assert_equals(imported.namespaceURI, originalAttr.namespaceURI);
+  assert_equals(imported.localName, originalAttr.localName);
+}, "Import an Attr node with namespace/prefix correctly.");
 </script>

third_party/WebKit/Source/core/dom/Document.cpp

@@ -1261,15 +1261,6 @@ Node* Document::importNode(Node* imported_node,
 
   // 2. Return a clone of node, with context object and the clone children flag
   // set if deep is true.
-  if (imported_node->IsAttributeNode()) {
-    // The following code doesn't create an Attr with namespace.  See
-    // crbug.com/812105.
-    return Attr::Create(
-        *this,
-        QualifiedName(g_null_atom, AtomicString(ToAttr(imported_node)->name()),
-                      g_null_atom),
-        ToAttr(imported_node)->value());
-  }
   return imported_node->Clone(
       *this, deep ? CloneChildrenFlag::kClone : CloneChildrenFlag::kSkip);
 }