Implement left property animation on InvalidatableStyleInterpolation

Source/core/style/ComputedStyle.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, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.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
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 class CORE_EXPORT ComputedStyle: public RefCounted<ComputedStyle> {
     friend class AnimatedStyleBuilder; // Used by Web Animations CSS. Sets the color styles
     friend class CSSAnimatableValueFactory; // Used by Web Animations CSS. Gets visited and unvisited colors separately.
     friend class CSSPropertyEquality; // Used by CSS animations. We can't allow them to animate based off visited colors.
     friend class ApplyStyleCommand; // Editing has to only reveal unvisited info.
     friend class EditingStyle; // Editing has to only reveal unvisited info.
     friend class ComputedStyleCSSValueMapping; // Needs to be able to see visited and unvisited colors for devtools.
     friend class StyleBuilderFunctions; // Sets color styles
     friend class CachedUAStyle; // Saves Border/Background information for later comparison.
+    friend class LengthPropertyFunctions; // Reads initial style values.
 
     // FIXME: When we stop resolving currentColor at style time, these can be removed.
     friend class CSSToStyleMap;
     friend class FilterOperationResolver;
     friend class StyleBuilderConverter;
     friend class StyleResolverState;
     friend class StyleResolver;
 protected:
 
     // non-inherited attributes
@@ skipping 1789 matching lines @@
 }
 
 inline bool ComputedStyle::hasPseudoElementStyle() const
 {
     return noninherited_flags.pseudoBits & PSEUDO_ELEMENT_MASK;
 }
 
 } // namespace blink
 
 #endif // ComputedStyle_h