Handle double literals in constant constructors.

pkg/compiler/lib/src/constants/constant_constructors.dart

Index: pkg/compiler/lib/src/constants/constant_constructors.dart
diff --git a/pkg/compiler/lib/src/constants/constant_constructors.dart b/pkg/compiler/lib/src/constants/constant_constructors.dart
index c389eefef3426ac639fc17bf2590b34ffdc32db9..874dab7c4f7a0584fbed397a22edd000a573b105 100644
--- a/pkg/compiler/lib/src/constants/constant_constructors.dart
+++ b/pkg/compiler/lib/src/constants/constant_constructors.dart
@@ -285,6 +285,11 @@ class ConstantConstructorComputer extends SemanticVisitor
   }
 
   @override
+  ConstantExpression visitLiteralDouble(LiteralDouble node) {
+    return new DoubleConstantExpression(node.value);
+  }
+
+  @override
   ConstantExpression visitLiteralBool(LiteralBool node) {
     return new BoolConstantExpression(node.value);
   }