Reapplying r5147 (caching maps for slow case objects)....

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 1003 matching lines @@
   // Helper function that governs the promotion policy from new space to
   // old.  If the object's old address lies below the new space's age
   // mark or if we've already filled the bottom 1/16th of the to space,
   // we try to promote this object.
   static inline bool ShouldBePromoted(Address old_address, int object_size);
 
   static int MaxObjectSizeInNewSpace() { return kMaxObjectSizeInNewSpace; }
 
   static void ClearJSFunctionResultCaches();
 
+  static void ClearNormalizedMapCaches();
+
   static GCTracer* tracer() { return tracer_; }
 
  private:
   static int reserved_semispace_size_;
   static int max_semispace_size_;
   static int initial_semispace_size_;
   static int max_old_generation_size_;
   static size_t code_range_size_;
 
   // For keeping track of how much data has survived
@@ skipping 945 matching lines @@
 
   // To speed up scavenge collections new space string are kept
   // separate from old space strings.
   static List<Object*> new_space_strings_;
   static List<Object*> old_space_strings_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_