Only call TextChanged on existing AXObjects. This avoids triggering the code which calls UpdateDist…

third_party/WebKit/Source/modules/accessibility/AXMenuList.cpp

Index: third_party/WebKit/Source/modules/accessibility/AXMenuList.cpp
diff --git a/third_party/WebKit/Source/modules/accessibility/AXMenuList.cpp b/third_party/WebKit/Source/modules/accessibility/AXMenuList.cpp
index 424319f162a34593f5e0b6fd5d010fa3024e6edb..193badcf95637cb913a5f84f0a9757f0ff5c2414 100644
--- a/third_party/WebKit/Source/modules/accessibility/AXMenuList.cpp
+++ b/third_party/WebKit/Source/modules/accessibility/AXMenuList.cpp
@@ -117,6 +117,8 @@ bool AXMenuList::CanSetFocusAttribute() const {
 }
 
 void AXMenuList::DidUpdateActiveOption(int option_index) {
+  bool suppress_notifications =
+      (GetNode() && !GetNode()->IsFinishedParsingChildren());
   const auto& child_objects = Children();
   if (!child_objects.IsEmpty()) {
     DCHECK(child_objects.size() == 1);
@@ -124,7 +126,7 @@ void AXMenuList::DidUpdateActiveOption(int option_index) {
 
     if (child_objects[0]->IsMenuListPopup()) {
       if (AXMenuListPopup* popup = ToAXMenuListPopup(child_objects[0].Get()))
-        popup->DidUpdateActiveOption(option_index);
+        popup->DidUpdateActiveOption(option_index, !suppress_notifications);
     }
   }