Add an API to V8 to get simple heap statistics.

src/heap.h

 // Copyright 2006-2008 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 242 matching lines @@
   }
   static int SemiSpaceSize() { return semispace_size_; }
   static int InitialSemiSpaceSize() { return initial_semispace_size_; }
   static int YoungGenerationSize() { return young_generation_size_; }
   static int OldGenerationSize() { return old_generation_size_; }
 
   // Returns the capacity of the heap in bytes w/o growing. Heap grows when
   // more spaces are needed until it reaches the limit.
   static int Capacity();
 
+  // Returns the amount of memory currently committed for the heap.
+  static int CommittedMemory();
+
   // Returns the available bytes in space w/o growing.
   // Heap doesn't guarantee that it can allocate an object that requires
   // all available bytes. Check MaxHeapObjectSize() instead.
   static int Available();
 
   // Returns the maximum object size in paged space.
   static inline int MaxObjectSizeInPagedSpace();
 
   // Returns of size of all objects residing in the heap.
   static int SizeOfObjects();
@@ skipping 1316 matching lines @@
   }
   static TranscendentalCache* caches_[kNumberOfCaches];
   Element elements_[kCacheSize];
   Type type_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_