Implement closed shadow adjustment for Element.offsetParent

third_party/WebKit/Source/core/layout/LayoutObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 3261 matching lines @@
             break;
 
         // Webkit specific extension where offsetParent stops at zoom level changes.
         if (effectiveZoom != ancestor->style()->effectiveZoom())
             break;
     }
 
     return node && node->isElementNode() ? toElement(node) : nullptr;
 }
 
+Element* LayoutObject::offsetParentForBinding() const

[eae, 2016/06/09 13:19:42]

How about a more descriptive name like nearestUnclosedAncestor?

[kochi, 2016/06/09 16:04:27]

I chose "unclosedOffsetParent()", as it still returns offsetParent,
but the difference is that it is expected to return unclosed one.

+{
+    Element* element = offsetParent();
+
+    while (element && (!element->isUnclosedNodeOf(*node()) || (element->isInShadowTree() && element->containingShadowRoot()->type() == ShadowRootType::UserAgent)))
+        element = element->layoutObject()->offsetParent();
+
+    return element;
+}
+
 PositionWithAffinity LayoutObject::createPositionWithAffinity(int offset, TextAffinity affinity)
 {
     // If this is a non-anonymous layoutObject in an editable area, then it's simple.
     if (Node* node = nonPseudoNode()) {
         if (!node->hasEditableStyle()) {
             // If it can be found, we prefer a visually equivalent position that is editable.
             const Position position = Position(node, offset);
             Position candidate = mostForwardCaretPosition(position, CanCrossEditingBoundary);
             if (candidate.anchorNode()->hasEditableStyle())
                 return PositionWithAffinity(candidate, affinity);
@@ skipping 416 matching lines @@
         const blink::LayoutObject* root = object1;
         while (root->parent())
             root = root->parent();
         root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
     } else {
         fprintf(stderr, "Cannot showLayoutTree. Root is (nil)\n");
     }
 }
 
 #endif