Turn styleWillChange |newStyle| into a reference

Source/core/rendering/RenderButton.cpp

Index: Source/core/rendering/RenderButton.cpp
diff --git a/Source/core/rendering/RenderButton.cpp b/Source/core/rendering/RenderButton.cpp
index 76accbfb3388247eeb63f24af9ea466f3b9c983c..4a58833036388f69ba2117ec3f5f007b366bb000 100644
--- a/Source/core/rendering/RenderButton.cpp
+++ b/Source/core/rendering/RenderButton.cpp
@@ -63,7 +63,7 @@ void RenderButton::removeChild(RenderObject* oldChild)
         m_inner->removeChild(oldChild);
 }
 
-void RenderButton::styleWillChange(StyleDifference diff, const RenderStyle* newStyle)
+void RenderButton::styleWillChange(StyleDifference diff, const RenderStyle& newStyle)
 {
     if (m_inner) {
         // RenderBlock::setStyle is going to apply a new style to the inner block, which
@@ -71,9 +71,9 @@ void RenderButton::styleWillChange(StyleDifference diff, const RenderStyle* newS
         // it right below. Here we change it back to 0 to avoid getting a spurious layout hint
         // because of the difference. Same goes for the other properties.
         // FIXME: Make this hack unnecessary.
-        m_inner->style()->setFlexGrow(newStyle->initialFlexGrow());
-        m_inner->style()->setMarginTop(newStyle->initialMargin());
-        m_inner->style()->setMarginBottom(newStyle->initialMargin());
+        m_inner->style()->setFlexGrow(newStyle.initialFlexGrow());
+        m_inner->style()->setMarginTop(newStyle.initialMargin());
+        m_inner->style()->setMarginBottom(newStyle.initialMargin());
     }
     RenderBlock::styleWillChange(diff, newStyle);
 }