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 f374cb7d65f5737e55b078eb7d0078baa52094bd..1b49579b701e64a47e0d0aef4babfa6965c2a5d9 100644
--- a/Source/core/frame/FrameView.cpp
+++ b/Source/core/frame/FrameView.cpp
@@ -1293,12 +1293,6 @@ 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.
@@ -1606,11 +1600,6 @@ 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();
     }
 }