Oilpan: simplify ContainerNode.removeChildren().

Source/core/dom/ContainerNode.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2013 Apple Inc. All rights reserved.
  *
  * 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.
@@ skipping 629 matching lines @@
         // Exclude this node when looking for removed focusedElement since only
         // children will be removed.
         // This must be later than willRemoveChildren, which might change focus
         // state of a child.
         document().removeFocusedElementOfSubtree(this, true);
 
         // Removing a node from a selection can cause widget updates.
         document().nodeChildrenWillBeRemoved(*this);
     }
 
+#if !ENABLE(OILPAN)
     // FIXME: Remove this NodeVector. Right now WebPluginContainerImpl::m_element is a
     // raw ptr which means the code below can drop the last ref to a plugin element and
     // then the code in UpdateSuspendScope::performDeferredWidgetTreeOperations will
     // try to destroy the plugin which will be a use-after-free. We should use a RefPtr
     // in the WebPluginContainerImpl instead.
     NodeVector removedChildren;
+#endif
     {
         HTMLFrameOwnerElement::UpdateSuspendScope suspendWidgetHierarchyUpdates;
 
         {
             EventDispatchForbiddenScope assertNoEventDispatch;
             ScriptForbiddenScope forbidScript;
 
+#if !ENABLE(OILPAN)
             removedChildren.reserveInitialCapacity(countChildren());
-
+#endif
             while (RefPtrWillBeRawPtr<Node> child = m_firstChild) {
                 removeBetween(0, child->nextSibling(), *child);
+#if !ENABLE(OILPAN)
                 removedChildren.append(child.get());
+#endif
                 notifyNodeRemoved(*child);
             }
         }
 
         ChildrenChange change = {AllChildrenRemoved, nullptr, nullptr, ChildrenChangeSourceAPI};
         childrenChanged(change);
     }
 
     if (action == DispatchSubtreeModifiedEvent)
         dispatchSubtreeModifiedEvent();
@@ skipping 794 matching lines @@
         return true;
 
     if (node->isElementNode() && toElement(node)->shadow())
         return true;
 
     return false;
 }
 #endif
 
 } // namespace blink