Handling of different types of empty alt

third_party/WebKit/public/web/WebAXEnums.h

 /*
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 305 matching lines @@
   kWebAXTextStyleUnderline = 1 << 2,
   kWebAXTextStyleLineThrough = 1 << 3
 };
 
 // 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 WebAXNameFrom {
   kWebAXNameFromUninitialized = -1,
   kWebAXNameFromAttribute = 0,
+  kWebAXNameFromAttributeExplicitlyEmpty,
   kWebAXNameFromCaption,
   kWebAXNameFromContents,
   kWebAXNameFromPlaceholder,
   kWebAXNameFromRelatedElement,
   kWebAXNameFromValue,
   kWebAXNameFromTitle,
 };
 
 // The source of the accessible description of an element. This is needed
 // because on some platforms this determines how the accessible description
@@ skipping 50 matching lines @@
 // empty vector.
 enum class WebAXObjectVectorAttribute {
   kAriaControls,
   kAriaDetails,
   kAriaFlowTo,
 };
 
 }  // namespace blink
 
 #endif