Fix one more DCHECK for FAST_STRING_WRAPPER_ELEMENTS

src/elements.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/elements.h"
 
 #include "src/arguments.h"
 #include "src/conversions.h"
 #include "src/factory.h"
 #include "src/messages.h"
@@ skipping 121 matching lines @@
         MemsetPointer(FixedArray::cast(to_base)->data_start() + start,
                       heap->the_hole_value(), length);
       }
     }
   }
   DCHECK((copy_size + static_cast<int>(to_start)) <= to_base->length() &&
          (copy_size + static_cast<int>(from_start)) <= from_base->length());
   if (copy_size == 0) return;
   FixedArray* from = FixedArray::cast(from_base);
   FixedArray* to = FixedArray::cast(to_base);
-  DCHECK(IsFastSmiOrObjectElementsKind(from_kind));
+  DCHECK(IsFastSmiOrObjectElementsKind(from_kind) ||
+         from_kind == FAST_STRING_WRAPPER_ELEMENTS);
   DCHECK(IsFastSmiOrObjectElementsKind(to_kind));
 
   WriteBarrierMode write_barrier_mode =
       (IsFastObjectElementsKind(from_kind) && IsFastObjectElementsKind(to_kind))
           ? UPDATE_WRITE_BARRIER
           : SKIP_WRITE_BARRIER;
   for (int i = 0; i < copy_size; i++) {
     Object* value = from->get(from_start + i);
     to->set(to_start + i, value, write_barrier_mode);
   }
@@ skipping 2519 matching lines @@
     }
   }
 
   DCHECK(j == result_len);
   return result_array;
 }
 
 ElementsAccessor** ElementsAccessor::elements_accessors_ = NULL;
 }  // namespace internal
 }  // namespace v8