Split StyleSurroundData::margin into four individual Lengths.

third_party/WebKit/Source/core/style/StyleSurroundData.cpp

 /*
  * Copyright (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #include "core/style/StyleSurroundData.h"
 
 namespace blink {
 
-StyleSurroundData::StyleSurroundData() : margin_(kFixed), padding_(kFixed) {}
+StyleSurroundData::StyleSurroundData()
+    : margin_left_(kFixed),
+      margin_right_(kFixed),
+      margin_top_(kFixed),
+      margin_bottom_(kFixed),
+      padding_(kFixed) {}
 
 StyleSurroundData::StyleSurroundData(const StyleSurroundData& o)
     : RefCounted<StyleSurroundData>(),
       left_(o.left_),
       right_(o.right_),
       top_(o.top_),
       bottom_(o.bottom_),
-      margin_(o.margin_),
+      margin_left_(o.margin_left_),
+      margin_right_(o.margin_right_),
+      margin_top_(o.margin_top_),
+      margin_bottom_(o.margin_bottom_),
       padding_(o.padding_),
       border_(o.border_) {}
 
 bool StyleSurroundData::operator==(const StyleSurroundData& o) const {
-  return left_ == o.left_ && right_ == o.right_ && top_ == o.top_ &&
-         bottom_ == o.bottom_ && margin_ == o.margin_ &&
+  return (left_ == o.left_ && right_ == o.right_ && top_ == o.top_ &&
+          bottom_ == o.bottom_) &&
+         (margin_left_ == o.margin_left_ && margin_right_ == o.margin_right_ &&
+          margin_top_ == o.margin_top_ && margin_bottom_ == o.margin_bottom_) &&
          padding_ == o.padding_ && border_ == o.border_;
 }
 
 }  // namespace blink