Add interface to get relative bounding box rect of AX objects.

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

 /*
  * Copyright (C) 2008 Apple 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 43 matching lines @@
 public:
     static AXLayoutObject* create(LayoutObject*, AXObjectCacheImpl&);
     ~AXLayoutObject() override;
 
     // Public, overridden from AXObject.
     LayoutObject* getLayoutObject() const final { return m_layoutObject; }
     LayoutRect elementRect() const override;
     LayoutBoxModelObject* getLayoutBoxModelObject() const;
     SkMatrix44 transformFromLocalParentFrame() const override;
     ScrollableArea* getScrollableAreaIfScrollable() const final;
+    void getRelativeBounds(AXObject** container, FloatRect& boundsInContainer, SkMatrix44& containerTransform) const override;
     AccessibilityRole determineAccessibilityRole() override;
     AccessibilityRole nativeAccessibilityRoleIgnoringAria() const override;
     void checkCachedElementRect() const;
     void updateCachedElementRect() const;
 
 protected:
     LayoutObject* m_layoutObject;
     mutable LayoutRect m_cachedElementRect;
     mutable LayoutRect m_cachedFrameRect;
     mutable IntPoint m_cachedScrollPosition;
@@ skipping 143 matching lines @@
     AXRange textControlSelection() const;
     int indexForVisiblePosition(const VisiblePosition&) const;
     AXLayoutObject* getUnignoredObjectFromNode(Node&) const;
 };
 
 DEFINE_AX_OBJECT_TYPE_CASTS(AXLayoutObject, isAXLayoutObject());
 
 } // namespace blink
 
 #endif // AXLayoutObject_h