Mark when we may have been invalidated to early out on repaintTreeAfterLayout.

Source/core/rendering/RenderListBox.cpp

Index: Source/core/rendering/RenderListBox.cpp
diff --git a/Source/core/rendering/RenderListBox.cpp b/Source/core/rendering/RenderListBox.cpp
index a9eb086d9a7655c9e43a7d9d2f4cbdfd5c8c68b0..8635b7ef9a087d9682568b10bb65a9edbcdbca69 100644
--- a/Source/core/rendering/RenderListBox.cpp
+++ b/Source/core/rendering/RenderListBox.cpp
@@ -192,6 +192,8 @@ void RenderListBox::layout()
     RenderBlockFlow::layout();
 
     if (m_vBar) {
+        setMayNeedInvalidation(true);
+
         bool enabled = numVisibleItems() < numItems();
         m_vBar->setEnabled(enabled);
         m_vBar->setProportion(numVisibleItems(), numItems());
@@ -202,6 +204,8 @@ void RenderListBox::layout()
     }
 
     if (m_scrollToRevealSelectionAfterLayout) {
+        setMayNeedInvalidation(true);
+
         LayoutStateDisabler layoutStateDisabler(*this);
         scrollToRevealSelection();
     }