Fix Win64 compilation problem.

src/spaces.h

 // Copyright 2011 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 1727 matching lines @@
            !p->IsFlagSet(Page::RESCAN_ON_EVACUATION) &&
            !p->WasSweptPrecisely();
   }
 
   void SetPagesToSweep(Page* first) {
     ASSERT(unswept_free_bytes_ == 0);
     if (first == &anchor_) first = NULL;
     first_unswept_page_ = first;
   }
 
-  void IncrementUnsweptFreeBytes(int by) {
+  void IncrementUnsweptFreeBytes(intptr_t by) {
     unswept_free_bytes_ += by;
   }
 
   void IncreaseUnsweptFreeBytes(Page* p) {
     ASSERT(ShouldBeSweptLazily(p));
     unswept_free_bytes_ += (p->area_size() - p->LiveBytes());
   }
 
-  void DecrementUnsweptFreeBytes(int by) {
+  void DecrementUnsweptFreeBytes(intptr_t by) {
     unswept_free_bytes_ -= by;
   }
 
   void DecreaseUnsweptFreeBytes(Page* p) {
     ASSERT(ShouldBeSweptLazily(p));
     unswept_free_bytes_ -= (p->area_size() - p->LiveBytes());
   }
 
   void ResetUnsweptFreeBytes() {
     unswept_free_bytes_ = 0;
@@ skipping 1059 matching lines @@
   }
   // Must be small, since an iteration is used for lookup.
   static const int kMaxComments = 64;
 };
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_SPACES_H_