Provide baseline for new GC infrastructure.

src/heap.h

 // Copyright 2010 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 1238 matching lines @@
   static GCCallback global_gc_prologue_callback_;
   static GCCallback global_gc_epilogue_callback_;
 
   // Support for computing object sizes during GC.
   static HeapObjectCallback gc_safe_size_of_old_object_;
   static int GcSafeSizeOfOldObject(HeapObject* object);
   static int GcSafeSizeOfOldObjectWithEncodedMap(HeapObject* object);
 
   // Update the GC state. Called from the mark-compact collector.
   static void MarkMapPointersAsEncoded(bool encoded) {
+    ASSERT(!encoded || !FLAG_new_gc);  // Encoding not used in new GC.
+
     gc_safe_size_of_old_object_ = encoded
         ? &GcSafeSizeOfOldObjectWithEncodedMap
         : &GcSafeSizeOfOldObject;
   }
 
   // Checks whether a global GC is necessary
   static GarbageCollector SelectGarbageCollector(AllocationSpace space);
 
   // Performs garbage collection
   // Returns whether there is a chance another major GC could
@@ skipping 836 matching lines @@
   // Return whether this object should be retained. If NULL is returned the
   // object has no references. Otherwise the address of the retained object
   // should be returned as in some GC situations the object has been moved.
   virtual Object* RetainAs(Object* object) = 0;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_