Use WeakCells in the optimized code map rather than traversing in pause.

src/heap/mark-compact.h

Index: src/heap/mark-compact.h
diff --git a/src/heap/mark-compact.h b/src/heap/mark-compact.h
index 1917ab58b1ec13f32d9fe87dffa8bcac29efdbc8..c021412a0f4c53aacf376b15b69cfd83a8de489c 100644
--- a/src/heap/mark-compact.h
+++ b/src/heap/mark-compact.h
@@ -685,11 +685,6 @@ class MarkCompactCollector {
 
   void AbortTransitionArrays();
 
-  // After all reachable objects have been marked, those entries within
-  // optimized code maps that became unreachable are removed, potentially
-  // trimming or clearing out the entire optimized code map.
-  void ProcessAndClearOptimizedCodeMaps();
-
   // -----------------------------------------------------------------------
   // Phase 2: Sweeping to clear mark bits and free non-live objects for
   // a non-compacting collection.