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 060429627ed051a83afd2b17efd34876e29d6707..3ae33ad72558e23781544165be3268953c0cf344 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"
@@ -1779,7 +1780,9 @@ 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)