Merge Blink code to cache SkTextBlob

sky/engine/platform/text/TextRun.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2006, 2007, 2011 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 14 matching lines @@
 #define SKY_ENGINE_PLATFORM_TEXT_TEXTRUN_H_
 
 #include "sky/engine/platform/PlatformExport.h"
 #include "sky/engine/platform/fonts/Glyph.h"
 #include "sky/engine/platform/geometry/FloatRect.h"
 #include "sky/engine/platform/text/TextDirection.h"
 #include "sky/engine/platform/text/TextPath.h"
 #include "sky/engine/wtf/RefCounted.h"
 #include "sky/engine/wtf/text/WTFString.h"
 
+class SkTextBlob;
+
 namespace blink {
 
 class FloatPoint;
 class Font;
 class GraphicsContext;
 class GlyphBuffer;
 class SimpleFontData;
 struct GlyphData;
 struct WidthIterator;
 
@@ skipping 193 matching lines @@
     m_allowTabs = allow;
     m_tabSize = size;
 }
 
 // Container for parameters needed to paint TextRun.
 struct TextRunPaintInfo {
     explicit TextRunPaintInfo(const TextRun& r)
         : run(r)
         , from(0)
         , to(r.length())
+        , cachedTextBlob(nullptr)
     {
     }
 
     const TextRun& run;
     int from;
     int to;
     FloatRect bounds;
+    RefPtr<const SkTextBlob>* cachedTextBlob;
 };
 
 }
 #endif  // SKY_ENGINE_PLATFORM_TEXT_TEXTRUN_H_