Fix repaint on :hover for empty elements with a border.

Source/core/rendering/RenderObject.cpp

Index: Source/core/rendering/RenderObject.cpp
diff --git a/Source/core/rendering/RenderObject.cpp b/Source/core/rendering/RenderObject.cpp
index d1d495c169724088b5fab5544249eceb017216c8..d927b6bc6692df9cbe9c1f679674864286e2c3ce 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -1900,9 +1900,14 @@ inline bool RenderObject::hasImmediateNonWhitespaceTextChildOrPropertiesDependen
     return false;
 }
 
+inline bool RenderObject::shouldRepaintIfTextOrColorChange() const
+{
+    return style()->hasBorder() || hasImmediateNonWhitespaceTextChildOrPropertiesDependentOnColor();
+}
+
 inline bool RenderObject::shouldRepaintForStyleDifference(StyleDifference diff) const
 {
-    return diff == StyleDifferenceRepaint || (diff == StyleDifferenceRepaintIfTextOrColorChange && hasImmediateNonWhitespaceTextChildOrPropertiesDependentOnColor());
+    return diff == StyleDifferenceRepaint || (diff == StyleDifferenceRepaintIfTextOrColorChange && shouldRepaintIfTextOrColorChange());

[rune, 2014/01/29 19:55:49]

This will trigger an unnecessary repaint if you have a border-color different
from currentColor, right?

[andersr, 2014/01/30 09:36:13]

Yes, correct.

I did not optimize that case because
hasImmediateNonWhitespaceTextChildOrPropertiesDependentOnColor() also does not
optimize that case. I was unsure if there was a reason for that (other than "not
worth it"). (Which pdr@ should know).

Perhaps it's worthwhile to add something like
RenderStyle::hasBorderWithCurrentColor?

 }
 
 void RenderObject::setStyle(PassRefPtr<RenderStyle> style)