Support JSON Schema properties with values in the JSON Schema Compiler.

tools/json_schema_compiler/test/idl_properties.idl

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Tests parsing the Properties interface.
+namespace idl_properties {
+  interface Properties {
+    // Integer property.
+    [value=42] static long first();
+
+    // Double property.
+    [value=42.0] static double second();
+
+    // String property.
+    [value="hello world"] static DOMString third();
+
+    // Unvalued property.
+    static long fourth();
+  };
+};