Make slot attributes unscopable

third_party/WebKit/Source/core/dom/Element.idl

Index: third_party/WebKit/Source/core/dom/Element.idl
diff --git a/third_party/WebKit/Source/core/dom/Element.idl b/third_party/WebKit/Source/core/dom/Element.idl
index 488dae9e783d58f427841ce560d03aa7e77efbbf..8642b56272c31fc59c3a9447e7b08f0d233b42ef 100644
--- a/third_party/WebKit/Source/core/dom/Element.idl
+++ b/third_party/WebKit/Source/core/dom/Element.idl
@@ -84,7 +84,7 @@ interface Element : Node {
     [RuntimeEnabled=ShadowDOMV1, RaisesException, CallWith=ScriptState, MeasureAs=ElementAttachShadow] ShadowRoot attachShadow(ShadowRootInit shadowRootInitDict);
     NodeList getDestinationInsertionPoints();
     [PerWorldBindings, ImplementedAs=openShadowRoot] readonly attribute ShadowRoot? shadowRoot;
-    [RuntimeEnabled=ShadowDOMV1, CEReactions, Reflect] attribute DOMString slot;
+    [RuntimeEnabled=ShadowDOMV1, Unscopeable, CEReactions, Reflect] attribute DOMString slot;
     [RuntimeEnabled=ShadowDOMV1, ImplementedAs=assignedSlotForBinding] readonly attribute HTMLSlotElement assignedSlot;
 
     // Pointer Lock