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

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 802 matching lines @@
     virtual const AtomicString& liveRegionStatus() const { return nullAtom; }
     virtual const AtomicString& liveRegionRelevant() const { return nullAtom; }
     virtual bool liveRegionAtomic() const { return false; }
     virtual bool liveRegionBusy() const { return false; }
 
     const AtomicString& containerLiveRegionStatus() const;
     const AtomicString& containerLiveRegionRelevant() const;
     bool containerLiveRegionAtomic() const;
     bool containerLiveRegionBusy() const;
 
-    // Location and click point in frame-relative coordinates.
+    // Location and click point in frame-relative coordinates. DEPRECATED, to be
+    // replaced by getRelativeBounds.
     virtual LayoutRect elementRect() const { return m_explicitElementRect; }
     void setElementRect(LayoutRect r) { m_explicitElementRect = r; }
     virtual void markCachedElementRectDirty() const;
     virtual IntPoint clickPoint();
 
     // Transformation relative to the parent frame, if local (otherwise returns identity).
+    // DEPRECATED, to be replaced by getRelativeBounds.
     virtual SkMatrix44 transformFromLocalParentFrame() const;
 
+    // NEW bounds calculation interface. Every object's bounding box is returned
+    // relative to a container object (which is guaranteed to be an ancestor) and
+    // optionally a transformation matrix that needs to be applied too.
+    // To compute the absolute bounding box of an element, start with its
+    // boundsInContainer and apply the transform. Then as long as its container is
+    // not null, walk up to its container and offset by the container's offset from
+    // origin, the container's scroll position if any, and apply the container's transform.
+    // Do this until you reach the root of the tree.
+    virtual void getRelativeBounds(AXObject** container, FloatRect& boundsInContainer, SkMatrix44& containerTransform) const;
+
     // Hit testing.
     // Called on the root AX object to return the deepest available element.
     virtual AXObject* accessibilityHitTest(const IntPoint&) const { return 0; }
     // Called on the AX object after the layout tree determines which is the right AXLayoutObject.
     virtual AXObject* elementAccessibilityHitTest(const IntPoint&) const;
 
     // High-level accessibility tree access. Other modules should only use these functions.
     const AXObjectVector& children();
     AXObject* parentObject() const;
     AXObject* parentObjectIfExists() const;
@@ skipping 142 matching lines @@
 
     static unsigned s_numberOfLiveAXObjects;
 };
 
 #define DEFINE_AX_OBJECT_TYPE_CASTS(thisType, predicate) \
     DEFINE_TYPE_CASTS(thisType, AXObject, object, object->predicate, object.predicate)
 
 } // namespace blink
 
 #endif // AXObject_h