Uses the activedescendant_changed event received from Blink to fire the right focus event

content/browser/accessibility/browser_accessibility_manager_mac.mm

Index: content/browser/accessibility/browser_accessibility_manager_mac.mm
diff --git a/content/browser/accessibility/browser_accessibility_manager_mac.mm b/content/browser/accessibility/browser_accessibility_manager_mac.mm
index 097eb4479097b51c2c9ffa1212571e19b11edb68..d8936615b53d9539492222755adea0d60242aa49 100644
--- a/content/browser/accessibility/browser_accessibility_manager_mac.mm
+++ b/content/browser/accessibility/browser_accessibility_manager_mac.mm
@@ -132,9 +132,13 @@ ui::AXTreeUpdate
 BrowserAccessibility* BrowserAccessibilityManagerMac::GetFocus() {
   // On Mac, list boxes should always get focus on the whole list, otherwise
   // information about the number of selected items will never be reported.
+  // For combo boxes, focus should stay on the combo box so the user will not be

[dmazzoni, 2016/04/29 20:55:54]

Consider doing this only for combo boxes where IsEditableText is true?

Sometimes people put role="combobox" on something that's more like a single-item
listbox and it maybe shouldn't behave the same.

+  // taken out of the combo box while typing.
   BrowserAccessibility* node = BrowserAccessibilityManager::GetFocus();
-  if (node && node->GetRole() == ui::AX_ROLE_LIST_BOX)
+  if (node && (node->GetRole() == ui::AX_ROLE_LIST_BOX ||
+               node->GetRole() == ui::AX_ROLE_COMBO_BOX)) {
     return node;
+  }
 
   // For other roles, follow the active descendant.
   return GetActiveDescendantFocus(node);
@@ -146,20 +150,6 @@ void BrowserAccessibilityManagerMac::NotifyAccessibilityEvent(
   if (!node->IsNative())
     return;
 
-  if (event_type == ui::AX_EVENT_FOCUS) {
-    BrowserAccessibility* active_descendant = GetActiveDescendantFocus(node);
-    if (active_descendant)
-      node = active_descendant;
-
-    if (node->GetRole() == ui::AX_ROLE_LIST_BOX_OPTION &&
-        node->HasState(ui::AX_STATE_SELECTED) &&
-        node->GetParent() &&
-        node->GetParent()->GetRole() == ui::AX_ROLE_LIST_BOX) {
-      node = node->GetParent();
-      SetFocus(*node);
-    }
-  }
-
   auto native_node = ToBrowserAccessibilityCocoa(node);
   DCHECK(native_node);
 
@@ -175,7 +165,10 @@ void BrowserAccessibilityManagerMac::NotifyAccessibilityEvent(
         // the combo box where the user might be typing.
         mac_notification = NSAccessibilitySelectedChildrenChangedNotification;
       } else {
-        mac_notification = NSAccessibilityFocusedUIElementChangedNotification;
+        // In all other cases we should post
+        // |NSAccessibilityFocusedUIElementChangedNotification|, but this is
+        // handled elsewhere.
+        return;
       }
       break;
     case ui::AX_EVENT_AUTOCORRECTION_OCCURED: