mFlags = kIsShared;
      nsSharedBufferHandle( CharT* aDataStart, CharT* aDataEnd, size_type aStorageLength, PRBool isSingleAllocation )          : nsBufferHandle<CharT>(aDataStart, aDataEnd),            mStorageLength(aStorageLength)        {          mFlags = kIsShared;          if ( isSingleAllocation )            mFlags |= kIsSingleAllocationWithBuffer;        }