IDL: Add build target for IDL dictionary impl generation in core

Source/core/testing/InternalDictionary.idl

Index: Source/core/testing/InternalDictionary.idl
diff --git a/Source/core/testing/InternalDictionary.idl b/Source/core/testing/InternalDictionary.idl
new file mode 100644
index 0000000000000000000000000000000000000000..4c36f19af6d6b43c09cd30856485222c844d15c8
--- /dev/null
+++ b/Source/core/testing/InternalDictionary.idl
@@ -0,0 +1,13 @@
+// Copyright 2014 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.
+
+[
+    GarbageCollected
+] dictionary InternalDictionary {
+    long longMember;
+    DOMString stringMember = "defaultStringValue";
+    boolean? booleanOrNullMember = null;
+    double? doubleOrNullMember;
+    sequence<DOMString> stringSequenceMember;
+};