Fix for issue 10534. Implement int.pow correctly. Note that int.pow is considerably slower than dou…

runtime/lib/math_patch.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import "dart:typed_data";
 
 // A VM patch of the dart:math library.
+
+// If [x] is an [int] and [exponent] is a non-negative [int], the result is
+// an [int], otherwise the result is a [double].
 patch num pow(num x, num exponent) {
-  if (exponent is int) {
+  if ((x is int) && (exponent is int) && (exponent >= 0)) {
     return x.pow(exponent);
   }
   // Double.pow will call exponent.toDouble().
   return x.toDouble().pow(exponent);
 }
 
 patch double atan2(num a, num b) => _atan2(a.toDouble(), b.toDouble());
 patch double sin(num value) => _sin(value.toDouble());
 patch double cos(num value) => _cos(value.toDouble());
 patch double tan(num value) => _tan(value.toDouble());
@@ skipping 92 matching lines @@
 
   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.
     return _prng._nextInt32();
   }
 }