Use relative bounding boxes throughout Chrome accessibility

ui/accessibility/ax_node.h

Index: ui/accessibility/ax_node.h
diff --git a/ui/accessibility/ax_node.h b/ui/accessibility/ax_node.h
index 54e443d9f1a84b7abb21b54feb867d81d20e37fc..e1415910c8275c7d09ea887fd9370d25b2c9c82b 100644
--- a/ui/accessibility/ax_node.h
+++ b/ui/accessibility/ax_node.h
@@ -44,7 +44,13 @@ class AX_EXPORT AXNode {
   // Update this node's location. This is separate from SetData just because
   // changing only the location is common and should be more efficient than
   // re-copying all of the data.
-  void SetLocation(const gfx::RectF& new_location);
+  //
+  // The node's location is stored as a relative bounding box, the ID of
+  // the element it's relative to, and an optional transformation matrix.
+  // See ax_node_data.h for details.
+  void SetLocation(int offset_container_id,
+                   const gfx::RectF& location,
+                   gfx::Transform* transform);
 
   // Set the index in parent, for example if siblings were inserted or deleted.
   void SetIndexInParent(int index_in_parent);