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

src/heap/mark-compact.h

 // Copyright 2012 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_MARK_COMPACT_H_
 #define V8_HEAP_MARK_COMPACT_H_
 
 #include "src/base/bits.h"
 #include "src/heap/spaces.h"
 
@@ skipping 663 matching lines @@
   // The linked list of all encountered weak maps is destroyed.
   void ClearWeakCollections();
 
   // We have to remove all encountered weak maps from the list of weak
   // collections when incremental marking is aborted.
   void AbortWeakCollections();
 
   void ProcessAndClearWeakCells();
   void AbortWeakCells();
 
-  // 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();
-
   // Process non-live references in maps and optimized code.
   void ProcessWeakReferences();
 
   // -----------------------------------------------------------------------
   // Phase 2: Sweeping to clear mark bits and free non-live objects for
   // a non-compacting collection.
   //
   //  Before: Live objects are marked and non-live objects are unmarked.
   //
   //   After: Live objects are unmarked, non-live regions have been added to
@@ skipping 164 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_MARK_COMPACT_H_