Make Failure inherit from MaybeObject instead of Object.

src/mark-compact.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 35 matching lines @@
 //
 // All methods are static.
 
 class MarkCompactCollector: public AllStatic {
  public:
   // Type of functions to compute forwarding addresses of objects in
   // compacted spaces.  Given an object and its size, return a (non-failure)
   // Object* that will be the object after forwarding.  There is a separate
   // allocation function for each (compactable) space based on the location
   // of the object before compaction.
-  typedef Object* (*AllocationFunction)(HeapObject* object, int object_size);
+  typedef MaybeObject* (*AllocationFunction)(HeapObject* object,
+                                             int object_size);
 
   // Type of functions to encode the forwarding address for an object.
   // Given the object, its size, and the new (non-failure) object it will be
   // forwarded to, encode the forwarding address.  For paged spaces, the
   // 'offset' input/output parameter contains the offset of the forwarded
   // object from the forwarding address of the previous live object in the
   // page as input, and is updated to contain the offset to be used for the
   // next live object in the same page.  For spaces using a different
   // encoding (ie, contiguous spaces), the offset parameter is ignored.
   typedef void (*EncodingFunction)(HeapObject* old_object,
@@ skipping 353 matching lines @@
 
   friend class UnmarkObjectVisitor;
   static void UnmarkObject(HeapObject* obj);
 #endif
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_MARK_COMPACT_H_