Improve SeqString::Truncate for latest allocated strings.

src/spaces-inl.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 333 matching lines @@
   heap->incremental_marking()->SetOldSpacePageFlags(chunk);
   return static_cast<LargePage*>(chunk);
 }
 
 
 intptr_t LargeObjectSpace::Available() {
   return ObjectSizeFor(heap()->isolate()->memory_allocator()->Available());
 }
 
 
-template <typename StringType>
-void NewSpace::ShrinkStringAtAllocationBoundary(String* string, int length) {
-  ASSERT(length <= string->length());
-  ASSERT(string->IsSeqString());
-  ASSERT(string->address() + StringType::SizeFor(string->length()) ==
-         allocation_info_.top);
-  Address old_top = allocation_info_.top;
-  allocation_info_.top =
-      string->address() + StringType::SizeFor(length);
-  string->set_length(length);
-  if (Marking::IsBlack(Marking::MarkBitFrom(string))) {
-    int delta = static_cast<int>(old_top - allocation_info_.top);
-    MemoryChunk::IncrementLiveBytesFromMutator(string->address(), -delta);
-  }
-}
-
-
 bool FreeListNode::IsFreeListNode(HeapObject* object) {
   Map* map = object->map();
   Heap* heap = object->GetHeap();
   return map == heap->raw_unchecked_free_space_map()
       || map == heap->raw_unchecked_one_pointer_filler_map()
       || map == heap->raw_unchecked_two_pointer_filler_map();
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_SPACES_INL_H_