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

Source/core/editing/EditingStrategy.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef EditingStrategy_h
 #define EditingStrategy_h
 
 #include "core/CoreExport.h"
 #include "core/dom/NodeTraversal.h"
 #include "core/dom/shadow/ComposedTreeTraversal.h"
+#include "wtf/Allocator.h"
 
 namespace blink {
 
 template <typename Strategy>
 class PositionAlgorithm;
 
 template <typename Strategy>
 class PositionIteratorAlgorithm;
 
 // Editing algorithm defined on node traversal.
 template <typename Traversal>
 class CORE_TEMPLATE_CLASS_EXPORT EditingAlgorithm : public Traversal {
+    STATIC_ONLY(EditingAlgorithm);
 public:
     static int caretMaxOffset(const Node&);
     // TODO(yosin) We should make following functions to take |Node&| instead
     // of |Node*|.
     static bool isEmptyNonEditableNodeInEditable(const Node*);
     static bool editingIgnoresContent(const Node*);
 
     // This method is used to create positions in the DOM. It returns the
     // maximum valid offset in a node. It returns 1 for some elements even
     // though they do not have children, which creates technically invalid DOM
     // Positions. Be sure to call |parentAnchoredEquivalent()| on a Position
     // before using it to create a DOM Range, or an exception will be thrown.
     static int lastOffsetForEditing(const Node*);
     static Node* rootUserSelectAllForNode(Node*);
 };
 
 extern template class CORE_EXTERN_TEMPLATE_EXPORT EditingAlgorithm<NodeTraversal>;
 extern template class CORE_EXTERN_TEMPLATE_EXPORT EditingAlgorithm<ComposedTreeTraversal>;
 
 // DOM tree version of editing algorithm
 using EditingStrategy = EditingAlgorithm<NodeTraversal>;
 // Composed tree version of editing algorithm
 using EditingInComposedTreeStrategy = EditingAlgorithm<ComposedTreeTraversal>;
 
 } // namespace blink
 
 #endif // EditingStrategy_h