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 8474a7ff7cecd4685e598a5e9463095ee981c207..d5e29a2a657bce2c53d3b6721eb51128f870b5ee 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,
@@ -1778,7 +1779,14 @@ private:
     Color lightingColor() const { return svgStyle()->lightingColor(); }
 
     void appendContent(PassOwnPtr<ContentData>);
-    StyleDifference repaintOnlyDiff(const RenderStyle& other, unsigned& changedContextSensitiveProperties) const;
+
+    bool diffNeedsLayoutAndRepaintLayer(const RenderStyle& other) const;
+    bool diffNeedsLayoutAndRepaintSelf(const RenderStyle& other) const;
+    bool diffNeedsLayoutOnly(const RenderStyle& other) const;
+    bool diffNeedsRepaintLayerOnly(const RenderStyle& other) const;
+    bool diffNeedsRepaintOnly(const RenderStyle& other) const;
+    bool diffNeedsRecompositeLayerOnly(const RenderStyle& other) const;
+    void addContextSensitiveDiffFlags(const RenderStyle& other, StyleDifference&) const;
 };
 
 inline int adjustForAbsoluteZoom(int value, float zoomFactor)