Auto merge of #18921 - mrobinson:incremental-stacking-context-ids, r=emilio

Fix duplicate stacking context creation for anonymous Flows

Anonymous nodes were previously creating duplicate stacking contexts,
one for each node in the anonymous node chain. This change eliminates
that for tables.

Additionally the use of stacking context ids based on node addresses is
no longer necessary since stacking contexts no longer control scrolling.
This is the first step in eliminating the dependency between node
addresses and ClipScrollNodes which causes issues like #16425.

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components/style/stylist.rs

@@ -763,13 +763,21 @@ impl Stylist {
 
         // For most (but not all) pseudo-elements, we inherit all values from the parent.
         let inherit_all = match *pseudo {
+            // Anonymous table flows shouldn't inherit their parents properties in order
+            // to avoid doubling up styles such as transformations.
+            PseudoElement::ServoAnonymousTableCell |
+            PseudoElement::ServoAnonymousTableRow |
             PseudoElement::ServoText |
             PseudoElement::ServoInputText => false,
             PseudoElement::ServoAnonymousBlock |
+
+            // For tables, we do want style to inherit, because TableWrapper is responsible
+            // for handling clipping and scrolling, while Table is responsible for creating
+            // stacking contexts. StackingContextCollectionFlags makes sure this is processed
+            // properly.
             PseudoElement::ServoAnonymousTable |
-            PseudoElement::ServoAnonymousTableCell |
-            PseudoElement::ServoAnonymousTableRow |
             PseudoElement::ServoAnonymousTableWrapper |
+
             PseudoElement::ServoTableWrapper |
             PseudoElement::ServoInlineBlockWrapper |
             PseudoElement::ServoInlineAbsolute => true,