Don't clip invalidation of composited scrolling contents

Source/core/rendering/RenderBox.cpp

Index: Source/core/rendering/RenderBox.cpp
diff --git a/Source/core/rendering/RenderBox.cpp b/Source/core/rendering/RenderBox.cpp
index 7fafa29ea302ac3326f9d2db3e4c2a0254b92f57..4ef201d6046e7e15002b0d2bbab97b7bf23fa602 100644
--- a/Source/core/rendering/RenderBox.cpp
+++ b/Source/core/rendering/RenderBox.cpp
@@ -874,7 +874,8 @@ void RenderBox::applyCachedClipAndScrollOffsetForPaintInvalidation(LayoutRect& p
     flipForWritingMode(paintRect);
     paintRect.move(-scrolledContentOffset()); // For overflow:auto/scroll/hidden.
 
-    // Do not clip scroll layer contents to reduce the number of paint invalidations while scrolling.
+    // Do not clip scroll layer contents because the compositor expects the whole layer
+    // to be always invalidated in-time.
     if (usesCompositedScrolling()) {
         flipForWritingMode(paintRect);
         return;