dart2js: Match the runtime int is check semantics at compile time.

pkg/compiler/lib/src/constants/values.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.
 
 library dart2js.constants.values;
 
 import '../common.dart';
 import '../core_types.dart';
 import '../dart_types.dart';
 import '../elements/elements.dart'
@@ skipping 46 matching lines @@
   /** Returns true if the constant is a list, a map or a constructed object. */
   bool get isObject => false;
   bool get isType => false;
   bool get isInterceptor => false;
   bool get isDummy => false;
 
   bool get isNaN => false;
   bool get isMinusZero => false;
   bool get isZero => false;
   bool get isOne => false;
+  bool get isPositiveInfinity => false;
+  bool get isNegativeInfinity => false;
 
   // TODO(johnniwinther): Replace with a 'type' getter.
   DartType getType(CoreTypes types);
 
   List<ConstantValue> getDependencies();
 
   accept(ConstantValueVisitor visitor, arg);
 
   /// The value of this constant in Dart syntax, if possible.
   ///
@@ skipping 195 matching lines @@
 
   bool get isNaN => primitiveValue.isNaN;
 
   // We need to check for the negative sign since -0.0 == 0.0.
   bool get isMinusZero => primitiveValue == 0.0 && primitiveValue.isNegative;
 
   bool get isZero => primitiveValue == 0.0;
 
   bool get isOne => primitiveValue == 1.0;
 
+  bool get isPositiveInfinity => primitiveValue == double.INFINITY;
+
+  bool get isNegativeInfinity => primitiveValue == -double.INFINITY;
+
   DartType getType(CoreTypes types) => types.doubleType;
 
   bool operator ==(var other) {
     if (other is !DoubleConstantValue) return false;
     DoubleConstantValue otherDouble = other;
     double otherValue = otherDouble.primitiveValue;
     if (primitiveValue == 0.0 && otherValue == 0.0) {
       return primitiveValue.isNegative == otherValue.isNegative;
     } else if (primitiveValue.isNaN) {
       return otherValue.isNaN;
@@ skipping 460 matching lines @@
 
   @override
   DartType getType(CoreTypes types) => const DynamicType();
 
   @override
   String toStructuredString() => 'NonConstant';
 
   @override
   String unparse() => '>>non-constant<<';
 }