Add sparse accessibility attribute interface to Blink

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

 /*
  * Copyright (C) 2012, 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 78 matching lines @@
 
   //
   // Overridden from AXObject.
   //
 
   void init() override;
   void detach() override;
   bool isDetached() const override { return !m_node; }
   bool isAXNodeObject() const final { return true; }
 
+  void getSparseAXAttributes(AXSparseAttributeClient&) const override;
+
   // Check object role or purpose.
   bool isAnchor() const final;
   bool isControl() const override;
   bool isControllingVideoElement() const;
   bool isEditable() const override { return isNativeTextControl(); }
   bool isEmbeddedObject() const final;
   bool isFieldset() const final;
   bool isHeading() const final;
   bool isHovered() const final;
   bool isImage() const final;
@@ skipping 124 matching lines @@
                                NameSources*,
                                bool* foundTextAlternative) const;
   float stepValueForRange() const;
   bool isDescendantOfElementType(const HTMLQualifiedName& tagName) const;
   String placeholderFromNativeAttribute() const;
 };
 
 }  // namespace blink
 
 #endif  // AXNodeObject_h