Separate repaint and layout requirements of StyleDifference (Step 3)

Source/core/rendering/style/StyleDifference.h

Index: Source/core/rendering/style/StyleDifference.h
diff --git a/Source/core/rendering/style/StyleDifference.h b/Source/core/rendering/style/StyleDifference.h
index 2d1e19c145d626f7fae065fec3300589e4afe250..9e23f3056fc642508efb1b094f183c45d3d7f236 100644
--- a/Source/core/rendering/style/StyleDifference.h
+++ b/Source/core/rendering/style/StyleDifference.h
@@ -8,10 +8,13 @@
 namespace WebCore {
 
 // This class represents the difference between two computed styles (RenderStyle).
-// The difference can be of 3 types:
-// - Layout difference
-// - Repaint difference
-// - Recompositing difference
+// The difference can be combination of 3 types according to the actions needed:
+// - Difference needing layout
+// - Difference needing repaint
+// - Difference needing recompositing layers
+//
+// Only directly needed actions are included. Indirect needed actions, such as
+// repaint caused by a layout change, are not included.
 class StyleDifference {
 public:
     StyleDifference()
@@ -30,11 +33,11 @@ public:
     void clearNeedsRepaint() { m_repaintType = NoRepaint; }
 
     // The object just needs to be repainted.
-    bool needsRepaintObjectOnly() const { return m_repaintType == RepaintObjectOnly; }
+    bool needsRepaintObject() const { return m_repaintType == RepaintObject; }
     void setNeedsRepaintObject()
     {
         if (!needsRepaintLayer())
-            m_repaintType = RepaintObjectOnly;
+            m_repaintType = RepaintObject;
     }
 
     // The layer and its descendant layers need to be repainted.
@@ -50,8 +53,6 @@ public:
     {
         if (!needsFullLayout())
             m_layoutType |= PositionedMovement;
-        // FIXME: This is temporary to keep the StyleDifferenceLegacy behavior.
-        m_repaintType = NoRepaint;
     }
 
     // Only overflow needs to be recomputed.
@@ -60,24 +61,17 @@ public:
     {
         if (!needsFullLayout())
             m_layoutType |= SimplifiedLayout;
-        // FIXME: This is temporary to keep the StyleDifferenceLegacy behavior.
-        m_repaintType = NoRepaint;
     }
 
     bool needsFullLayout() const { return m_layoutType == FullLayout; }
-    void setNeedsFullLayout()
-    {
-        m_layoutType = FullLayout;
-        // FIXME: This is temporary to keep the StyleDifferenceLegacy behavior.
-        m_repaintType = NoRepaint;
-    }
+    void setNeedsFullLayout() { m_layoutType = FullLayout; }
 
 private:
     unsigned m_needsRecompositeLayer : 1;
 
     enum RepaintType {
         NoRepaint = 0,
-        RepaintObjectOnly,
+        RepaintObject,
         RepaintLayer
     };
     unsigned m_repaintType : 2;