Simply rules for compositing fixed position elements

Source/core/frame/FrameView.cpp

Index: Source/core/frame/FrameView.cpp
diff --git a/Source/core/frame/FrameView.cpp b/Source/core/frame/FrameView.cpp
index d5a120e4e2d75d93036764a89e23a9327afd929b..b6842aa6cb0aa1d33189b9dffb912b2a00a69ecd 100644
--- a/Source/core/frame/FrameView.cpp
+++ b/Source/core/frame/FrameView.cpp
@@ -1287,12 +1287,6 @@ bool FrameView::scrollContentsFastPath(const IntSize& scrollDelta, const IntRect
         if (layer->compositingState() == PaintsIntoOwnBacking)
             continue;
 
-        if (layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForBoundsOutOfView
-            || layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForNoVisibleContent) {
-            // Don't invalidate for invisible fixed layers.
-            continue;
-        }
-
         if (layer->hasAncestorWithFilterOutsets()) {
             // If the fixed layer has a blur/drop-shadow filter applied on at least one of its parents, we cannot
             // scroll using the fast path, otherwise the outsets of the filter will be moved around the page.
@@ -1595,11 +1589,6 @@ void FrameView::updateFixedElementPaintInvalidationRectsAfterScroll()
         if (layer->compositingState() == PaintsIntoOwnBacking)
             continue;
 
-        // Also don't need to do this for invisible items.
-        if (layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForBoundsOutOfView
-            || layer->viewportConstrainedNotCompositedReason() == RenderLayer::NotCompositedForNoVisibleContent)
-            continue;
-
         layer->repainter().computeRepaintRectsIncludingNonCompositingDescendants();
     }
 }