Make RenderObject::style() return a const object

Source/core/rendering/RenderQuote.cpp

Index: Source/core/rendering/RenderQuote.cpp
diff --git a/Source/core/rendering/RenderQuote.cpp b/Source/core/rendering/RenderQuote.cpp
index 9ff595ad55b0570a6a3d5fb85fe74a4d88a303d4..27c5297602f01dce9cf4e38cedbc67df051f979c 100644
--- a/Source/core/rendering/RenderQuote.cpp
+++ b/Source/core/rendering/RenderQuote.cpp
@@ -265,11 +265,11 @@ void RenderQuote::updateText()
 
     RenderTextFragment* fragment = findFragmentChild();
     if (fragment) {
-        fragment->setStyle(style());
+        fragment->setStyle(mutableStyle());
         fragment->setContentString(m_text.impl());
     } else {
         fragment = new RenderTextFragment(&document(), m_text.impl());
-        fragment->setStyle(style());
+        fragment->setStyle(mutableStyle());
         addChild(fragment);
     }
 }