Handling of different types of empty alt

third_party/WebKit/Source/modules/accessibility/AXObject.h

 /*
  * Copyright (C) 2008, 2009, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nuanti Ltd.
  *
  * 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.
@@ skipping 344 matching lines @@
   virtual void AddObjectVectorAttribute(AXObjectVectorAttribute,
                                         HeapVector<Member<AXObject>>&) = 0;
 };
 
 // The source of the accessible name of an element. This is needed
 // because on some platforms this determines how the accessible name
 // is exposed.
 enum AXNameFrom {
   kAXNameFromUninitialized = -1,
   kAXNameFromAttribute = 0,
+  kAXNameFromAttributeExplicitlyEmpty,
   kAXNameFromCaption,
   kAXNameFromContents,
   kAXNameFromPlaceholder,
   kAXNameFromRelatedElement,
   kAXNameFromValue,
   kAXNameFromTitle,
 };
 
 // The potential native HTML-based text (name, description or placeholder)
 // sources for an element.  See
@@ skipping 752 matching lines @@
   static unsigned number_of_live_ax_objects_;
 };
 
 #define DEFINE_AX_OBJECT_TYPE_CASTS(thisType, predicate)           \
   DEFINE_TYPE_CASTS(thisType, AXObject, object, object->predicate, \
                     object.predicate)
 
 }  // namespace blink
 
 #endif  // AXObject_h