Replace support for event.path.

src/utils/polymer.dom.html

@@ -320,6 +320,10 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
     get localTarget() {
       return this.event.target;
     }
+
+    get path() {
+      return this.event.composedPath();
+    }
   }
 
   Polymer.dom = function(obj) {

test/unit/shady-events.html

@@ -253,6 +253,24 @@ suite('ShadyDOM event patching', function() {
     assert.equal(el.events[0], el.$.child);
     assert.equal(el.events[1], el);
   });
+
+  test('Polymer.dom events', function(done) {
+    var el = fixture('scoped');
+    el.addEventListener('composed', function(e) {
+      assert.equal(Polymer.dom(e).rootTarget, el.$.scoped);
+      assert.equal(Polymer.dom(e).localTarget, el);
+      let nodes = [];
+      let p = el.$.scoped;
+      while (p) {
+        nodes.push(p);
+        p = p.parentNode || p.host;
+      }
+      nodes.push(window);
+      assert.deepEqual(Array.from(Polymer.dom(e).path), nodes);
+      done();
+    });
+    el.fireComposed();
+  });
 });
 </script>
 </body>