Avoid copying value in ComputedStyle CoW comparions (compareEqual)

third_party/WebKit/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
@@ skipping 64 matching lines @@
 #include "wtf/LeakAnnotations.h"
 #include "wtf/RefCounted.h"
 #include "wtf/Vector.h"
 #include <memory>
 
 template <typename T, typename U>
 inline bool compareEqual(const T& t, const U& u) {
   return t == static_cast<T>(u);
 }
 
+template <typename T>
+inline bool compareEqual(const T& a, const T& b) {
+  return a == b;
+}
+
 #define SET_VAR(group, variable, value)      \
   if (!compareEqual(group->variable, value)) \
   group.access()->variable = value
 
 #define SET_NESTED_VAR(group, base, variable, value) \
   if (!compareEqual(group->base->variable, value))   \
   group.access()->base.access()->variable = value
 
 #define SET_VAR_WITH_SETTER(group, getter, setter, value) \
   if (!compareEqual(group->getter(), value))              \
@@ skipping 4018 matching lines @@
   m_nonInheritedData.m_pseudoBits |= 1 << (pseudo - 1);
 }
 
 inline bool ComputedStyle::hasPseudoElementStyle() const {
   return m_nonInheritedData.m_pseudoBits & ElementPseudoIdMask;
 }
 
 }  // namespace blink
 
 #endif  // ComputedStyle_h