New bigint implementation in the vm.

runtime/lib/double.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.
 
 class _Double extends _Num implements double {
   factory _Double.fromInteger(int value)
       native "Double_doubleFromInteger";
 
   Type get runtimeType => double;
 
@@ skipping 116 matching lines @@
     if (lowerLimit.compareTo(upperLimit) > 0) {
       throw new ArgumentError(lowerLimit);
     }
     if (lowerLimit.isNaN) return lowerLimit;
     if (this.compareTo(lowerLimit) < 0) return lowerLimit;
     if (this.compareTo(upperLimit) > 0) return upperLimit;
     return this;
   }
 
   int toInt() native "Double_toInt";
+  _Bigint _toBigint() { return toInt()._toBigint(); }
   double toDouble() { return this; }
 
   static const int CACHE_SIZE_LOG2 = 3;
   static const int CACHE_LENGTH = 1 << (CACHE_SIZE_LOG2 + 1);
   static const int CACHE_MASK = CACHE_LENGTH - 1;
   // Each key (double) followed by its toString result.
   static final List _cache = new List(CACHE_LENGTH);
   static int _cacheEvictIndex = 0;
 
   String toString() {
@@ skipping 116 matching lines @@
         return EQUAL;
       }
     } else if (isNaN) {
       return other.isNaN ? EQUAL : GREATER;
     } else {
       // Other is NaN.
       return LESS;
     }
   }
 }