Oilpan: Remove most WillBe types from the code base

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

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 // https://dom.spec.whatwg.org/#interface-treewalker
 
 [
     SetWrapperReferenceTo(NodeFilter filter),
-    WillBeGarbageCollected,
+    GarbageCollected,
 ] interface TreeWalker {
     [SameObject] readonly attribute Node root;
     readonly attribute unsigned long whatToShow;
     readonly attribute NodeFilter? filter;
     attribute Node currentNode;
 
     [RaisesException] Node? parentNode();
     [RaisesException] Node? firstChild();
     [RaisesException] Node? lastChild();
     [RaisesException] Node? previousSibling();
     [RaisesException] Node? nextSibling();
     [RaisesException] Node? previousNode();
     [RaisesException] Node? nextNode();
 };