Infer types of double literals.

pkg/front_end/testcases/inference/simple_literal_double.dart

Index: pkg/front_end/testcases/inference/simple_literal_double.dart
diff --git a/pkg/front_end/testcases/inference/simple_literal_double.dart b/pkg/front_end/testcases/inference/simple_literal_double.dart
new file mode 100644
index 0000000000000000000000000000000000000000..ca789222456656679d545c1f0c1aa23c9ab72462
--- /dev/null
+++ b/pkg/front_end/testcases/inference/simple_literal_double.dart
@@ -0,0 +1,12 @@
+// Copyright (c) 2017, 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.md file.
+
+/*@testedFeatures=inference*/
+library test;
+
+var /*@topType=double*/ a = 1.2;
+
+main() {
+  var /*@type=double*/ b = 3.4;
+}