Make RenderObject::style() return a const object

Source/core/rendering/line/BreakingContextInlineHeaders.h

Index: Source/core/rendering/line/BreakingContextInlineHeaders.h
diff --git a/Source/core/rendering/line/BreakingContextInlineHeaders.h b/Source/core/rendering/line/BreakingContextInlineHeaders.h
index 324b8bc9f6b70c82df1f06e03f35b3ae46558216..ee6652538442c52e0c136e2a56b4d20b31322b21 100644
--- a/Source/core/rendering/line/BreakingContextInlineHeaders.h
+++ b/Source/core/rendering/line/BreakingContextInlineHeaders.h
@@ -119,8 +119,8 @@ private:
     RenderObject* m_lastObject;
     RenderObject* m_nextObject;
 
-    RenderStyle* m_currentStyle;
-    RenderStyle* m_blockStyle;
+    const RenderStyle* m_currentStyle;
+    const RenderStyle* m_blockStyle;
 
     LineInfo& m_lineInfo;
 
@@ -502,7 +502,7 @@ inline float firstPositiveWidth(const WordMeasurements& wordMeasurements)
 
 inline float measureHyphenWidth(RenderText* renderer, const Font& font, TextDirection textDirection)
 {
-    RenderStyle* style = renderer->style();
+    const RenderStyle* style = renderer->style();
     return font.width(constructTextRun(renderer, font,
         style->hyphenString().string(), style, style->direction()));
 }
@@ -553,7 +553,7 @@ inline bool BreakingContext::handleText(WordMeasurements& wordMeasurements, bool
         }
     }
 
-    RenderStyle* style = renderText->style(m_lineInfo.isFirstLine());
+    const RenderStyle* style = renderText->style(m_lineInfo.isFirstLine());
     const Font& font = style->font();
     bool isFixedPitch = font.isFixedPitch();
 
@@ -899,7 +899,7 @@ inline void BreakingContext::commitAndUpdateLineBreakIfNeeded()
     }
 }
 
-inline IndentTextOrNot requiresIndent(bool isFirstLine, bool isAfterHardLineBreak, RenderStyle* style)
+inline IndentTextOrNot requiresIndent(bool isFirstLine, bool isAfterHardLineBreak, const RenderStyle* style)
 {
     IndentTextOrNot shouldIndentText = DoNotIndentText;
     if (isFirstLine || (isAfterHardLineBreak && style->textIndentLine()) == TextIndentEachLine)