Only call TextChanged on existing AXObjects

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

 /*
  * Copyright (C) 2014, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 567 matching lines @@
   while (node) {
     if (AXObjectImpl* obj = Get(node)) {
       obj->SelectionChanged();
       return;
     }
     node = node->parentNode();
   }
 }
 
 void AXObjectCacheImpl::TextChanged(Node* node) {
-  TextChanged(GetOrCreate(node));
+  AXObjectImpl* axObject = Get(node);
+  if (!axObject)

[dmazzoni, 2017/06/14 18:38:14]

I think you could remove this null-check since TextChanged(AXObjectImpl*)
already does that. Throughout the whole file pretty much all methods allow null
as an argument to keep the code simple.

I'd just write TextChanged(Get(node))

and add a comment saying we don't want to do anything if there's no existing
object because layout may not be clean and/or updatedistribution may be needed

[aboxhall, 2017/06/14 18:46:05]

Great, done.

+    return;
+  TextChanged(axObject);
 }
 
 void AXObjectCacheImpl::TextChanged(LayoutObject* layout_object) {
-  TextChanged(GetOrCreate(layout_object));
+  AXObjectImpl* axObject = Get(layout_object);
+  if (!axObject)

[dmazzoni, 2017/06/14 18:38:14]

Same

[aboxhall, 2017/06/14 18:46:05]

Done.

+    return;
+  TextChanged(axObject);
 }
 
 void AXObjectCacheImpl::TextChanged(AXObjectImpl* obj) {
   if (!obj)
     return;
 
   obj->TextChanged();
   PostNotification(obj, AXObjectCacheImpl::kAXTextChanged);
 }
 
@@ skipping 671 matching lines @@
   visitor->Trace(document_);
   visitor->Trace(node_object_mapping_);
 
   visitor->Trace(objects_);
   visitor->Trace(notifications_to_post_);
 
   AXObjectCache::Trace(visitor);
 }
 
 }  // namespace blink