Keep track of fixed positioning in accessibility tree.

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

 /*
  * 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 2046 matching lines @@
     html_element = ToHTMLElement(GetNode());
   if (html_element && IsLabelableElement(html_element)) {
     if (ToLabelableElement(html_element)->labels() &&
         ToLabelableElement(html_element)->labels()->length() > 0)
       return true;
   }
 
   return false;
 }
 
-void AXNodeObject::GetRelativeBounds(
-    AXObject** out_container,
-    FloatRect& out_bounds_in_container,
-    SkMatrix44& out_container_transform) const {
+void AXNodeObject::GetRelativeBounds(AXObject** out_container,
+                                     FloatRect& out_bounds_in_container,
+                                     SkMatrix44& out_container_transform,
+                                     bool& out_is_fixed_positioned) const {
   if (LayoutObjectForRelativeBounds()) {
     AXObject::GetRelativeBounds(out_container, out_bounds_in_container,
-                                out_container_transform);
+                                out_container_transform,
+                                out_is_fixed_positioned);
     return;
   }
 
   *out_container = nullptr;
   out_bounds_in_container = FloatRect();
   out_container_transform.setIdentity();
 
   // First check if it has explicit bounds, for example if this element is tied
   // to a canvas path. When explicit coordinates are provided, the ID of the
   // explicit container element that the coordinates are relative to must be
   // provided too.
   if (!explicit_element_rect_.IsEmpty()) {
     *out_container = AxObjectCache().ObjectFromAXID(explicit_container_id_);
     if (*out_container) {
       out_bounds_in_container = FloatRect(explicit_element_rect_);
       return;
     }
   }
 
   // If it's in a canvas but doesn't have an explicit rect, get the bounding
   // rect of its children.
   if (GetNode()->parentElement()->IsInCanvasSubtree()) {
     Vector<FloatRect> rects;
     for (Node& child : NodeTraversal::ChildrenOf(*GetNode())) {
       if (child.IsHTMLElement()) {
         if (AXObject* obj = AxObjectCache().Get(&child)) {
           AXObject* container;
           FloatRect bounds;
-          obj->GetRelativeBounds(&container, bounds, out_container_transform);
+          obj->GetRelativeBounds(&container, bounds, out_container_transform,
+                                 out_is_fixed_positioned);
           if (container) {
             *out_container = container;
             rects.push_back(bounds);
           }
         }
       }
     }
 
     if (*out_container) {
       out_bounds_in_container = UnionRect(rects);
       return;
     }
   }
 
   // If this object doesn't have an explicit element rect or computable from its
   // children, for now, let's return the position of the ancestor that does have
   // a position, and make it the width of that parent, and about the height of a
   // line of text, so that it's clear the object is a child of the parent.
   for (AXObject* position_provider = ParentObject(); position_provider;
        position_provider = position_provider->ParentObject()) {
     if (position_provider->IsAXLayoutObject()) {
       position_provider->GetRelativeBounds(
-          out_container, out_bounds_in_container, out_container_transform);
+          out_container, out_bounds_in_container, out_container_transform,
+          out_is_fixed_positioned);
       if (*out_container)
         out_bounds_in_container.SetSize(
             FloatSize(out_bounds_in_container.Width(),
                       std::min(10.0f, out_bounds_in_container.Height())));
       break;
     }
   }
 }
 
 static Node* GetParentNodeForComputeParent(Node* node) {
@@ skipping 1122 matching lines @@
     return String();
   return ToTextControlElement(node)->StrippedPlaceholder();
 }
 
 DEFINE_TRACE(AXNodeObject) {
   visitor->Trace(node_);
   AXObject::Trace(visitor);
 }
 
 }  // namespace blink