Subtree caching implementation in blink-core

Source/core/layout/LayoutText.h

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004-2009, 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 140 matching lines @@
     void styleWillChange(StyleDifference, const ComputedStyle&) final { }
     void styleDidChange(StyleDifference, const ComputedStyle* oldStyle) override;
 
     virtual void setTextInternal(PassRefPtr<StringImpl>);
     virtual UChar previousCharacter() const;
 
     void addLayerHitTestRects(LayerHitTestRects&, const DeprecatedPaintLayer* currentLayer, const LayoutPoint& layerOffset, const LayoutRect& containerRect) const override;
 
     virtual InlineTextBox* createTextBox(int start, unsigned short length); // Subclassed by SVG.
 
-    void invalidateDisplayItemClients(const LayoutBoxModelObject& paintInvalidationContainer) const override;
+    void invalidateDisplayItemClients(const LayoutBoxModelObject& paintInvalidationContainer) override;
 
 private:
     void computePreferredLogicalWidths(float leadWidth);
     void computePreferredLogicalWidths(float leadWidth, HashSet<const SimpleFontData*>& fallbackFonts, FloatRect& glyphBounds);
 
     bool computeCanUseSimpleFontCodePath() const;
 
     // Make length() private so that callers that have a LayoutText*
     // will use the more efficient textLength() instead, while
     // callers with a LayoutObject* can continue to use length().
@@ skipping 73 matching lines @@
 inline LayoutText* Text::layoutObject() const
 {
     return toLayoutText(CharacterData::layoutObject());
 }
 
 void applyTextTransform(const ComputedStyle*, String&, UChar);
 
 } // namespace blink
 
 #endif // LayoutText_h