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

src/heap/objects-visiting.h

Index: src/heap/objects-visiting.h
diff --git a/src/heap/objects-visiting.h b/src/heap/objects-visiting.h
index e213a13e6878c018ca90c209ad7da977070b6c3a..4122b4b64268348ae3774edeee9da6a587005561 100644
--- a/src/heap/objects-visiting.h
+++ b/src/heap/objects-visiting.h
@@ -377,10 +377,6 @@ class StaticMarkingVisitor : public StaticVisitorBase {
   static void MarkMapContents(Heap* heap, Map* map);
   static void MarkTransitionArray(Heap* heap, TransitionArray* transitions);
 
-  // Mark pointers in the optimized code map that should act as strong
-  // references, possibly treating some entries weak.
-  static void MarkOptimizedCodeMap(Heap* heap, FixedArray* code_map);
-
   // Code flushing support.
   INLINE(static bool IsFlushable(Heap* heap, JSFunction* function));
   INLINE(static bool IsFlushable(Heap* heap, SharedFunctionInfo* shared_info));