Bug 1564071 - Disable paint skipping for scroll frames that contain a sticky element inside a CSS filter. r=mstange

Differential Revision: https://phabricator.services.mozilla.com/D37604

--HG--
extra : moz-landing-system : lando

layout/generic/nsFrame.cpp

@@ -3535,6 +3535,14 @@ void nsIFrame::BuildDisplayListForStackingContext(
         aBuilder, this, &resultList, stickyASR,
         aBuilder->CurrentActiveScrolledRoot());
     ct.TrackContainer(resultList.GetTop());
+
+    // If the sticky element is inside a filter, annotate the scroll frame that
+    // scrolls the filter as having out-of-flow content inside a filter (this
+    // inhibits paint skipping).
+    if (aBuilder->GetFilterASR() && aBuilder->GetFilterASR() == stickyASR) {
+      aBuilder->GetFilterASR()
+          ->mScrollableFrame->SetHasOutOfFlowContentInsideFilter();
+    }
   }
 
   /* If there's blending, wrap up the list in a blend-mode item. Note

layout/painting/nsDisplayList.h

@@ -1128,6 +1128,8 @@ class nsDisplayListBuilder {
     return mActiveScrolledRootForRootScrollframe;
   }
 
+  const ActiveScrolledRoot* GetFilterASR() const { return mFilterASR; }
+
   /**
    * Transfer off main thread animations to the layer.  May be called
    * with aBuilder and aItem both null, but only if the caller has