Reapply the non-MathExtras parts of

Source/wtf/CryptographicallyRandomNumber.cpp

 /*
  * Copyright (c) 1996, David Mazieres <dm@uun.org>
  * Copyright (c) 2008, Damien Miller <djm@openbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies.
  *
  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
@@ skipping 59 matching lines @@
     inline uint32_t getWord();
 
     ARC4Stream m_stream;
     int m_count;
     Mutex m_mutex;
 };
 
 ARC4Stream::ARC4Stream()
 {
     for (int n = 0; n < 256; n++)
-        s[n] = n;
+        s[n] = static_cast<uint8_t>(n);
     i = 0;
     j = 0;
 }
 
 ARC4RandomNumberGenerator::ARC4RandomNumberGenerator()
     : m_count(0)
 {
 }
 
 void ARC4RandomNumberGenerator::addRandomData(unsigned char* data, int length)
@@ skipping 85 matching lines @@
 {
     return sharedRandomNumberGenerator().randomNumber();
 }
 
 void cryptographicallyRandomValues(void* buffer, size_t length)
 {
     sharedRandomNumberGenerator().randomValues(buffer, length);
 }
 
 }