Remove the USE(OS_RANDOMNESS) guard.

Source/wtf/Platform.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007-2009 Torch Mobile, Inc.
  * Copyright (C) 2010, 2011 Research In Motion Limited. 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.
@@ skipping 441 matching lines @@
 #endif
 #endif /* !defined(HAVE_ACCESSIBILITY) */
 
 #if OS(UNIX)
 #define HAVE_ERRNO_H 1
 #define HAVE_MMAP 1   
 #define HAVE_SIGNAL_H 1
 #define HAVE_STRINGS_H 1
 #define HAVE_SYS_PARAM_H 1
 #define HAVE_SYS_TIME_H 1 
-#define WTF_USE_OS_RANDOMNESS 1
 #define WTF_USE_PTHREADS 1
 #endif /* OS(UNIX) */
 
 #if OS(UNIX) && !OS(ANDROID)
 #define HAVE_LANGINFO_H 1
 #endif
 
 #if (OS(FREEBSD) || OS(OPENBSD)) && !defined(__GLIBC__)
 #define HAVE_PTHREAD_NP_H 1
 #endif
@@ skipping 29 matching lines @@
 #define HAVE_HOSTED_CORE_ANIMATION 1
 #define HAVE_MADV_FREE_REUSE 1
 
 #endif /* OS(DARWIN) */
 
 #if OS(WINDOWS)
 #define HAVE_SYS_TIMEB_H 1
 #define HAVE_ALIGNED_MALLOC 1
 #define HAVE_ISDEBUGGERPRESENT 1
 #define HAVE_VIRTUALALLOC 1
-#define WTF_USE_OS_RANDOMNESS 1
 #endif
 
 /* FIXME: When all platforms' compositors can compute their own filter outsets, we should remove this define. 
    https://bugs.webkit.org/show_bug.cgi?id=112830 */
 #if USE(CG)
 #define HAVE_COMPOSITOR_FILTER_OUTSETS 1
 #endif
 
 #if !defined(WTF_USE_3D_GRAPHICS)
 #define WTF_USE_3D_GRAPHICS 1
 #endif
 
 #if !defined(ENABLE_THREADING_LIBDISPATCH) && HAVE(DISPATCH_H)
 #define ENABLE_THREADING_LIBDISPATCH 1
 #elif !defined(ENABLE_THREADING_OPENMP) && defined(_OPENMP)
 #define ENABLE_THREADING_OPENMP 1
 #elif !defined(THREADING_GENERIC)
 #define ENABLE_THREADING_GENERIC 1
 #endif
 
 #endif /* WTF_Platform_h */