Retain layout sizes by pixel axis

core/src/layout_diagnostics.rs

@@ -33,6 +33,7 @@ pub(crate) enum Counter {
     SizeReads,
     HintHits,
     HintMisses,
+    RetainedSizeHits,
     ReuseAttempts,
     ReuseExact,
     ReuseMoved,
@@ -67,6 +68,7 @@ impl Counter {
         "draw-result size reads",
         "hint hits",
         "hint misses",
+        "retained size hits",
         "reuse attempts",
         "reuse exact",
         "reuse moved",