Bug 1522809 - Nodes with name="attributes" break the markup view r=rcaliman

This is another very specific issue.

If you have `<img name="attributes"/>` in the dom then `document.attributes` will return the `<img>` tag.

In the source we bail if `!this.rawNode.attributes` but if we are on the document node this returns the image tag. Because the image tag is not a `NamedNodeMap` trying to iterate over the tag throws the error.

There is a test file [here](https://bugzilla.mozilla.org/attachment.cgi?id=9040577).

Differential Revision: https://phabricator.services.mozilla.com/D18340

--HG--
extra : moz-landing-system : lando

devtools/server/actors/inspector/node.js

@@ -293,7 +293,10 @@ const NodeActor = protocol.ActorClassWithSpec(nodeSpec, {
   },
 
   writeAttrs: function() {
-    if (!this.rawNode.attributes) {
+    // If the node has no attributes or this.rawNode is the document node and a
+    // node with `name="attributes"` exists in the DOM we need to bail.
+    if (!this.rawNode.attributes ||
+        !(this.rawNode.attributes instanceof NamedNodeMap)) {
       return undefined;
     }
 

devtools/shared/builtin-modules.js

@@ -24,6 +24,7 @@ const {
   DOMQuad,
   DOMRect,
   HeapSnapshot,
+  NamedNodeMap,
   NodeFilter,
   StructuredCloneHolder,
   TelemetryStopwatch,
@@ -291,6 +292,7 @@ exports.globals = {
   DOMParser,
   DOMPoint,
   DOMQuad,
+  NamedNodeMap,
   NodeFilter,
   DOMRect,
   Element,