Optimize repaint on FrameView resize

Source/core/rendering/RenderObject.h

Index: Source/core/rendering/RenderObject.h
diff --git a/Source/core/rendering/RenderObject.h b/Source/core/rendering/RenderObject.h
index 7ffb86cf19aca82d227df40ec668be67628ae97a..5d51dde2a689f4a342eacbd084da78b94a3b5b97 100644
--- a/Source/core/rendering/RenderObject.h
+++ b/Source/core/rendering/RenderObject.h
@@ -104,6 +104,11 @@ enum MarkingBehavior {
     MarkContainingBlockChain,
 };
 
+enum RepaintLayerBehavior {
+    RepaintLayer,
+    DontRepaintLayer,
+};
+
 enum MapCoordinatesMode {
     IsFixed = 1 << 0,
     UseTransforms = 1 << 1,
@@ -611,7 +616,7 @@ public:
     Element* offsetParent() const;
 
     void markContainingBlocksForLayout(bool scheduleRelayout = true, RenderObject* newRoot = 0, SubtreeLayoutScope* = 0);
-    void setNeedsLayout(MarkingBehavior = MarkContainingBlockChain, SubtreeLayoutScope* = 0);
+    void setNeedsLayout(MarkingBehavior = MarkContainingBlockChain, SubtreeLayoutScope* = 0, RepaintLayerBehavior = RepaintLayer);
     void clearNeedsLayout();
     void setChildNeedsLayout(MarkingBehavior = MarkContainingBlockChain, SubtreeLayoutScope* = 0);
     void setNeedsPositionedMovementLayout();
@@ -1269,7 +1274,7 @@ inline bool RenderObject::isBeforeOrAfterContent() const
     return isBeforeContent() || isAfterContent();
 }
 
-inline void RenderObject::setNeedsLayout(MarkingBehavior markParents, SubtreeLayoutScope* layouter)
+inline void RenderObject::setNeedsLayout(MarkingBehavior markParents, SubtreeLayoutScope* layouter, RepaintLayerBehavior repaintLayer)
 {
     ASSERT(!isSetNeedsLayoutForbidden());
     bool alreadyNeededLayout = m_bitfields.selfNeedsLayout();
@@ -1277,7 +1282,8 @@ inline void RenderObject::setNeedsLayout(MarkingBehavior markParents, SubtreeLay
     if (!alreadyNeededLayout) {
         if (markParents == MarkContainingBlockChain && (!layouter || layouter->root() != this))
             markContainingBlocksForLayout(true, 0, layouter);
-        if (hasLayer())
+        // FIXME: This may be incorrect, but needed at least because StyleDifferenceLayout implies repaint for now.
+        if (repaintLayer == RepaintLayer && hasLayer())

[eseidel, 2014/03/28 16:36:41]

This repaint call is just wrong IMO.  See crbug.com/325569.  Layout's job is to
adjust if needed and only issue repaints if needed.  It should not be assumed
that just because we mark something as needing layout it will need repaint.

This call was added years ago, but I think we should work to remove it now.

             setLayerNeedsFullRepaint();
     }
 }