Add "platforms" key in IDL schema compiler.

tools/json_schema_compiler/test/idl_namespace_chromeos.idl

Index: tools/json_schema_compiler/test/idl_namespace_chromeos.idl
diff --git a/chrome/test/functional/perf/endure_graphs/config.js b/tools/json_schema_compiler/test/idl_namespace_chromeos.idl
similarity index 59%
copy from chrome/test/functional/perf/endure_graphs/config.js
copy to tools/json_schema_compiler/test/idl_namespace_chromeos.idl
index cb9fa3d90b699b35fc244cd73d8859afcd80bee9..1d654f2dbc511eb2616031aaccbb727055c5bdee 100644
--- a/chrome/test/functional/perf/endure_graphs/config.js
+++ b/tools/json_schema_compiler/test/idl_namespace_chromeos.idl
@@ -1,8 +1,10 @@
-// Copyright (c) 2013 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.
-
-var Config = {
-  buildslave: 'Chrome Endure Bots',
-  title: 'Chrome Endure Tests',
-};
+// Copyright (c) 2013 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 the case of a namespace with chromeos platforms.
+
+[platforms=("chromeos")]
+namespace idl_namespace_chromeos {
+
+};