Implement aging of maps embedded in optimized code.

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 598 matching lines @@
                      AllocationSpace to_old_space);
 
   bool TryPromoteObject(HeapObject* object, int object_size);
 
   void InvalidateCode(Code* code);
 
   void ClearMarkbits();
 
   bool abort_incremental_marking() const { return abort_incremental_marking_; }
 
+  bool reduce_memory_footprint() const { return reduce_memory_footprint_; }
+
   bool is_compacting() const { return compacting_; }
 
   MarkingParity marking_parity() { return marking_parity_; }
 
   // Concurrent and parallel sweeping support. If required_freed_bytes was set
   // to a value larger than 0, then sweeping returns after a block of at least
   // required_freed_bytes was freed. If required_freed_bytes was set to zero
   // then the whole given space is swept. It returns the size of the maximum
   // continuous freed memory chunk.
   int SweepInParallel(PagedSpace* space, int required_freed_bytes);
@@ skipping 317 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_MARK_COMPACT_H_