The older shadow root should act as a parent tree scope

Author: arv

src/wrappers/ShadowRoot.js

@@ -28,11 +28,12 @@
     // DocumentFragment instance. Override that.
     rewrap(node, this);
 
-    this.treeScope_ = new TreeScope(this, getTreeScope(hostWrapper));
-
     var oldShadowRoot = hostWrapper.shadowRoot;
     nextOlderShadowTreeTable.set(this, oldShadowRoot);
 
+    this.treeScope_ =
+        new TreeScope(this, getTreeScope(oldShadowRoot || hostWrapper));
+
     shadowHostTable.set(this, hostWrapper);
   }
   ShadowRoot.prototype = Object.create(DocumentFragment.prototype);

test/js/TreeScope.js

@@ -71,7 +71,7 @@ suite('TreeScope', function() {
     assert.equal(ts1.parent, null);
     assert.equal(ts2.parent, ts1);
     assert.equal(ts3.parent, ts2);
-    assert.equal(ts4.parent, ts1);
+    assert.equal(ts4.parent, ts2);
 
     var div2 = document.createElement('div');
     div2.appendChild(a);