Add counters that automatically track object sizes and counts.

src/d8.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 49 matching lines @@
 
 
 // A set of counters and associated information.  An instance of this
 // class is stored directly in the memory-mapped counters file if
 // the --map-counters options is used
 class CounterCollection {
  public:
   CounterCollection();
   Counter* GetNextCounter();
  private:
-  static const unsigned kMaxCounters = 256;
+  static const unsigned kMaxCounters = 512;
   uint32_t magic_number_;
   uint32_t max_counters_;
   uint32_t max_name_size_;
   uint32_t counters_in_use_;
   Counter counters_[kMaxCounters];
 };
 
 
 class CounterMap {
  public:
@@ skipping 320 matching lines @@
                                            ExternalArrayType type,
                                            int32_t element_size);
   static void ExternalArrayWeakCallback(Persistent<Value> object, void* data);
 };
 
 
 }  // namespace v8
 
 
 #endif  // V8_D8_H_