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

src/heap/gc-tracer.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_GC_TRACER_H_
 #define V8_HEAP_GC_TRACER_H_
 
 #include "src/base/platform/platform.h"
 #include "src/globals.h"
 
@@ skipping 91 matching lines @@
       MC_MARK_FINISH_INCREMENTAL,
       MC_MARK_PREPARE_CODE_FLUSH,
       MC_MARK_ROOT,
       MC_MARK_TOPOPT,
       MC_MARK_RETAIN_MAPS,
       MC_MARK_WEAK_CLOSURE,
       MC_MARK_STRING_TABLE,
       MC_MARK_WEAK_REFERENCES,
       MC_MARK_GLOBAL_HANDLES,
       MC_MARK_CODE_FLUSH,
-      MC_MARK_OPTIMIZED_CODE_MAPS,
       MC_STORE_BUFFER_CLEAR,
       MC_SLOTS_BUFFER_CLEAR,
       MC_SWEEP,
       MC_SWEEP_NEWSPACE,
       MC_SWEEP_OLDSPACE,
       MC_SWEEP_CODE,
       MC_SWEEP_CELL,
       MC_SWEEP_MAP,
       MC_SWEEP_ABORTED,
       MC_EVACUATE_PAGES,
@@ skipping 479 matching lines @@
 
   // Counts how many tracers were started without stopping.
   int start_counter_;
 
   DISALLOW_COPY_AND_ASSIGN(GCTracer);
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_GC_TRACER_H_