Change age-mark to not expect pages to be in increasing order.

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 371 matching lines @@
 
   enum MemoryChunkFlags {
     IS_EXECUTABLE,
     WAS_SWEPT_CONSERVATIVELY,
     CONTAINS_ONLY_DATA,
     POINTERS_TO_HERE_ARE_INTERESTING,
     POINTERS_FROM_HERE_ARE_INTERESTING,
     SCAN_ON_SCAVENGE,
     IN_FROM_SPACE,  // Mutually exclusive with IN_TO_SPACE.
     IN_TO_SPACE,    // All pages in new space has one of these two set.
+    NEW_SPACE_BELOW_AGE_MARK,
     NUM_MEMORY_CHUNK_FLAGS
   };
 
   void SetFlag(int flag) {
     flags_ |= (1 << flag);
   }
 
   void ClearFlag(int flag) {
     flags_ &= ~(1 << flag);
   }
@@ skipping 1233 matching lines @@
     if (next_page == &anchor_) return false;
     current_page_ = next_page;
     return true;
   }
 
   // Resets the space to using the first page.
   void Reset();
 
   // Age mark accessors.
   Address age_mark() { return age_mark_; }
-  void set_age_mark(Address mark) { age_mark_ = mark; }
+  void set_age_mark(Address mark);
 
   // If we don't have these here then SemiSpace will be abstract.  However
   // they should never be called.
   virtual intptr_t Size() {
     UNREACHABLE();
     return 0;
   }
 
   virtual bool ReserveSpace(int bytes) {
     UNREACHABLE();
@@ skipping 808 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_