Landing for Justin Schuh.

Seed the random number generator in Windows with rand_s 

This is a quick fix for m9. It works on Windows Chrome because the random device is already initialized before permissions are dropped for the Chrome sandbox. The same trick isn't possible on Linux or Mac. 

I think the long-term solution is to provide an interface for supplying v8 with a true random number generator. Then Chrome can just hook up the generator from base/rand_util.h 

BUG=http://code.google.com/p/v8/issues/detail?id=936 
TEST=None.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5889 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/platform-win32.cc

@@ -54,6 +54,11 @@
 #define _WIN32_WINNT 0x501
 #endif
 
+// Required before stdlib.h inclusion for cryptographically strong rand_s.
+#ifndef _CRT_RAND_S
+#define _CRT_RAND_S
+#endif  // _CRT_RAND_S
+
 #include <windows.h>
 
 #include <time.h>  // For LocalOffset() implementation.
@@ -584,11 +589,8 @@ char* Time::LocalTimezone() {
 
 void OS::Setup() {
   // Seed the random number generator.
-  // Convert the current time to a 64-bit integer first, before converting it
-  // to an unsigned. Going directly can cause an overflow and the seed to be
-  // set to all ones. The seed will be identical for different instances that
-  // call this setup code within the same millisecond.
-  uint64_t seed = static_cast<uint64_t>(TimeCurrentMillis());
+  unsigned int seed;
+  CHECK_EQ(rand_s(&seed), 0);
   srand(static_cast<unsigned int>(seed));
 }