Correctly fire active descendant changes for more roles

chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs

Index: chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs
diff --git a/chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs b/chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs
index e8f8475cbda6d72897e4793e480ee88d8862eab9..51d9da674c380b632905b37d77cb72b1d718262f 100644
--- a/chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs
+++ b/chrome/browser/resources/chromeos/chromevox/cvox2/background/background_test.extjs
@@ -870,3 +870,29 @@ TEST_F('BackgroundTest', 'ButtonNameValueDescription', function() {
         .replay();
   });
 });
+
+TEST_F('BackgroundTest', 'ActiveDescendantOnPopupButton', function() {
+  var mockFeedback = this.createMockFeedback();
+  this.runWithLoadedTree(function(root) {/*!
+    <button id="a" aria-activedescendant="b" aria-haspopup="true">a</button>
+    <p id="b">b</p>
+    <p id="c">c</p>
+    <script>
+      var alt = false;
+      setInterval(function() {
+        var id = alt ? 'b' : 'c';
+        document.getElementById('a').setAttribute('aria-activedescendant', id);
+        alt = !alt;
+      }, 500);
+    </script>
+  */}, function(root) {
+    root.find({role: RoleType.popUpButton}).focus();
+    mockFeedback.expectSpeech('a')
+        .expectSpeech('b')
+        .expectSpeech('Button')
+        .expectSpeech('b')
+        .expectSpeech('c')
+        .expectSpeech('b')
+        .replay();
+  });
+});