Fix store buffer ensure space heuristics.

src/store-buffer.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 93 matching lines @@
     old_top_ = reinterpret_cast<Address*>(top);
   }
 
   bool old_buffer_is_sorted() { return old_buffer_is_sorted_; }
   bool old_buffer_is_filtered() { return old_buffer_is_filtered_; }
 
   // Goes through the store buffer removing pointers to things that have
   // been promoted.  Rebuilds the store buffer completely if it overflowed.
   void SortUniq();
 
+  bool SpaceAvailable(intptr_t space_needed);
   void EnsureSpace(intptr_t space_needed);
   void Verify();
 
   bool PrepareForIteration();
 
 #ifdef DEBUG
   void Clean();
   // Slow, for asserts only.
   bool CellIsInStoreBuffer(Address cell);
 #endif
@@ skipping 122 matching lines @@
   }
 
  private:
   StoreBuffer* store_buffer_;
   bool stored_state_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_STORE_BUFFER_H_