Separate repaint and layout requirements of StyleDifference (Step 1)

Source/core/rendering/style/RenderStyle.h

Index: Source/core/rendering/style/RenderStyle.h
diff --git a/Source/core/rendering/style/RenderStyle.h b/Source/core/rendering/style/RenderStyle.h
index 765a9ef6b8a69f921693a344a5110c92c48e4454..b223bf75b219a4a68e38bf55ee145cf3409ce6cd 100644
--- a/Source/core/rendering/style/RenderStyle.h
+++ b/Source/core/rendering/style/RenderStyle.h
@@ -41,6 +41,7 @@
 #include "core/rendering/style/StyleBackgroundData.h"
 #include "core/rendering/style/StyleBoxData.h"
 #include "core/rendering/style/StyleDeprecatedFlexibleBoxData.h"
+#include "core/rendering/style/StyleDifference.h"
 #include "core/rendering/style/StyleFilterData.h"
 #include "core/rendering/style/StyleFlexibleBoxData.h"
 #include "core/rendering/style/StyleGridData.h"
@@ -360,7 +361,7 @@ public:
     static StyleRecalcChange stylePropagationDiff(const RenderStyle* oldStyle, const RenderStyle* newStyle);
 
     // Computes how much visual invalidation the style change causes: layout, repaint or recomposite.
-    StyleDifference visualInvalidationDiff(const RenderStyle&, unsigned& changedContextSensitiveProperties) const;
+    StyleDifference visualInvalidationDiff(const RenderStyle&) const;
 
     enum IsAtShadowBoundary {
         AtShadowBoundary,
@@ -1776,7 +1777,9 @@ private:
     Color lightingColor() const { return svgStyle()->lightingColor(); }
 
     void appendContent(PassOwnPtr<ContentData>);
-    StyleDifference repaintOnlyDiff(const RenderStyle& other, unsigned& changedContextSensitiveProperties) const;
+
+    StyleDifferenceLegacy visualInvalidationDiffLegacy(const RenderStyle&, unsigned& changedContextSensitiveProperties) const;
+    StyleDifferenceLegacy repaintOnlyDiff(const RenderStyle& other, unsigned& changedContextSensitiveProperties) const;
 };
 
 inline int adjustForAbsoluteZoom(int value, float zoomFactor)