Implement closed shadow adjustment for Element.offsetParent

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

Index: third_party/WebKit/Source/core/layout/LayoutObject.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.cpp b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
index 7b7996ca542c27b32613429569ccd690bd5d2d9f..b86045ea20a4e8284f30ef6f4520d6aaeb13ac77 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
@@ -3279,6 +3279,16 @@ Element* LayoutObject::offsetParent() const
     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.