Make classes and structures in core/dom fast-allocated.

Source/core/dom/Node.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004-2011, 2014 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.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
@@ skipping 502 matching lines @@
             m_data.m_rareData->setLayoutObject(layoutObject);
         else
             m_data.m_layoutObject = layoutObject;
     }
 
     // Use these two methods with caution.
     LayoutBox* layoutBox() const;
     LayoutBoxModelObject* layoutBoxModelObject() const;
 
     struct AttachContext {
+        STACK_ALLOCATED();
         ComputedStyle* resolvedStyle;
         bool performingReattach;
 
         AttachContext() : resolvedStyle(nullptr), performingReattach(false) { }
     };
 
     // Attaches this node to the layout tree. This calculates the style to be applied to the node and creates an
     // appropriate LayoutObject which will be inserted into the tree (except when the style has display: none). This
     // makes the node visible in the FrameView.
     virtual void attach(const AttachContext& = AttachContext());
@@ skipping 366 matching lines @@
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showNode(const blink::Node*);
 void showTree(const blink::Node*);
 void showNodePath(const blink::Node*);
 #endif
 
 #endif // Node_h