Remove the USE(OS_RANDOMNESS) guard.

Source/wtf/OSRandomSource.h

 /*
  * Copyright (C) Google, Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 10 matching lines @@
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
  */
 
 #ifndef WTF_OSRandomSource_h
 #define WTF_OSRandomSource_h
 
 namespace WTF {
 
-#if USE(OS_RANDOMNESS)
 // This function attempts to fill buffer with randomness from the operating
 // system.  If insufficient randomness is available, the buffer will be
 // partially filled.  Rather than calling this function directly, consider
 // calling cryptographicallyRandomNumber or cryptographicallyRandomValues.
 void cryptographicallyRandomValuesFromOS(unsigned char* buffer, size_t length);
-#endif
 
 }
 
 #endif