Don't always fully repaint on viewport resize

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 5226c90054a431aacfdb1869e050292a28cc66ab..aa5791f87345927384a54f6578aa623af2b12c95 100644
--- a/Source/core/rendering/style/RenderStyle.h
+++ b/Source/core/rendering/style/RenderStyle.h
@@ -405,6 +405,8 @@ public:
 
     bool hasBackgroundImage() const { return m_background->background().hasImage(); }
     bool hasFixedBackgroundImage() const { return m_background->background().hasFixedImage(); }
+    bool backgroundImageNeedsFullRepaintOnContainerWidthChange() const { return m_background->background().needsFullRepaintOnContainerWidthChange(); }
+    bool backgroundImageNeedsFullRepaintOnContainerHeightChange() const { return m_background->background().needsFullRepaintOnContainerHeightChange(); }
 
     bool hasEntirelyFixedBackground() const;