Make RenderObject::style() return a const object

Source/core/layout/MultiColumnFragmentainerGroup.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 
 #include "core/layout/MultiColumnFragmentainerGroup.h"
 
 #include "core/layout/LayoutMultiColumnSet.h"
 
@@ skipping 288 matching lines @@
         LayoutUnit contentLogicalTop = m_columnSet.logicalTop() - multicolBlock->borderAndPaddingBefore();
         height -= contentLogicalTop;
     }
     height -= logicalTop();
     return max(height, LayoutUnit(1)); // Let's avoid zero height, as that would probably cause an infinite amount of columns to be created.
 }
 
 LayoutUnit MultiColumnFragmentainerGroup::calculateMaxColumnHeight() const
 {
     RenderBlockFlow* multicolBlock = m_columnSet.multiColumnBlockFlow();
-    LayoutStyle* multicolStyle = multicolBlock->style();
+    const LayoutStyle& multicolStyle = multicolBlock->styleRef();
     LayoutUnit availableHeight = m_columnSet.multiColumnFlowThread()->columnHeightAvailable();
     LayoutUnit maxColumnHeight = availableHeight ? availableHeight : LayoutFlowThread::maxLogicalHeight();
-    if (!multicolStyle->logicalMaxHeight().isMaxSizeNone()) {
-        LayoutUnit logicalMaxHeight = multicolBlock->computeContentLogicalHeight(multicolStyle->logicalMaxHeight(), -1);
+    if (!multicolStyle.logicalMaxHeight().isMaxSizeNone()) {
+        LayoutUnit logicalMaxHeight = multicolBlock->computeContentLogicalHeight(multicolStyle.logicalMaxHeight(), -1);
         if (logicalMaxHeight != -1 && maxColumnHeight > logicalMaxHeight)
             maxColumnHeight = logicalMaxHeight;
     }
     return heightAdjustedForRowOffset(maxColumnHeight);
 }
 
 void MultiColumnFragmentainerGroup::setAndConstrainColumnHeight(LayoutUnit newHeight)
 {
     m_columnHeight = newHeight;
     if (m_columnHeight > m_maxColumnHeight)
@@ skipping 177 matching lines @@
     append(MultiColumnFragmentainerGroup(m_columnSet));
     return last();
 }
 
 void MultiColumnFragmentainerGroupList::deleteExtraGroups()
 {
     shrink(1);
 }
 
 } // namespace blink