Maintain a FixedArray for the optimized code map.

src/heap/objects-visiting-inl.h

Index: src/heap/objects-visiting-inl.h
diff --git a/src/heap/objects-visiting-inl.h b/src/heap/objects-visiting-inl.h
index 08e9092cb857674e85cb09d4b18503b0ede15296..34a0ab2515cae850926963a810485ad5239c24af 100644
--- a/src/heap/objects-visiting-inl.h
+++ b/src/heap/objects-visiting-inl.h
@@ -458,16 +458,16 @@ void StaticMarkingVisitor<StaticVisitor>::VisitSharedFunctionInfo(
     shared->ClearTypeFeedbackInfoAtGCTime();
   }
   if (FLAG_flush_optimized_code_cache) {
-    if (!shared->optimized_code_map()->IsSmi()) {
+    if (!shared->OptimizedCodeMapIsCleared()) {
       // Always flush the optimized code map if requested by flag.
       shared->ClearOptimizedCodeMap();
     }
   } else {
-    if (!shared->optimized_code_map()->IsSmi()) {
+    if (!shared->OptimizedCodeMapIsCleared()) {
       // Treat some references within the code map weakly by marking the
       // code map itself but not pushing it onto the marking deque. The
       // map will be processed after marking.
-      FixedArray* code_map = FixedArray::cast(shared->optimized_code_map());
+      FixedArray* code_map = shared->optimized_code_map();
       MarkOptimizedCodeMap(heap, code_map);
     }
   }