Support encoding of NaN, infinity and negative infinity.

pkg/compiler/lib/src/serialization/serialization.dart

Index: pkg/compiler/lib/src/serialization/serialization.dart
diff --git a/pkg/compiler/lib/src/serialization/serialization.dart b/pkg/compiler/lib/src/serialization/serialization.dart
index b1418f64907cfc912b62ea9c51bb1a5094980933..27baa606aac3ca56167929915407e4493b5e4b8c 100644
--- a/pkg/compiler/lib/src/serialization/serialization.dart
+++ b/pkg/compiler/lib/src/serialization/serialization.dart
@@ -540,13 +540,21 @@ abstract class AbstractDecoder<K> {
   /// If no value is associated with [key], then if [isOptional] is `true`,
   /// [defaultValue] is returned, otherwise an exception is thrown.
   double getDouble(K key, {bool isOptional: false, double defaultValue}) {
-    double value = _map[_getKeyValue(key)];
+    var value = _map[_getKeyValue(key)];
     if (value == null) {
       if (isOptional || defaultValue != null) {
         return defaultValue;
       }
       throw new StateError("double value '$key' not found in $_map.");
     }
+    // Support alternative encoding of NaN and +/- infinity for JSON.
+    if (value == 'NaN') {
+      return double.NAN;
+    } else if (value == '-Infinity') {
+      return double.NEGATIVE_INFINITY;
+    } else if (value == 'Infinity') {
+      return double.INFINITY;
+    }
     return value;
   }