- Do not rely on time to seed the default PRNG.

runtime/lib/math_patch.dart

Index: runtime/lib/math_patch.dart
===================================================================
--- runtime/lib/math_patch.dart	(revision 33702)
+++ runtime/lib/math_patch.dart	(working copy)
@@ -154,13 +154,11 @@
   static const _A = 0xffffda61;
 
   // Use a singleton Random object to get a new seed if no seed was passed.
-  static var _prng = null;
+  static var _prng = new Random(_initialSeed());

[siva, 2014/03/17 17:46:02]

This can potentially result in an overflow error when the flag
--throw_on_javascript_int_overflow flag is used.

 
+  static int _initialSeed() native "Random_initialSeed";
+
   static int _nextSeed() {
-    if (_prng == null) {
-      // TODO(iposva): Use system to get a random seed.
-      _prng = new Random(new DateTime.now().millisecondsSinceEpoch);
-    }
     // Trigger the PRNG once to change the internal state.
     _prng._nextState();
     return _prng._state[kSTATE_LO];