Remove dart generator code from json schema compiler.

tools/json_schema_compiler/dart_test/dictionaries.idl

-// Copyright (c) 2012 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.
-
-// This comment is for the dictionaries namespace.
-namespace dictionaries {
-  // Documentation for ComplexType.
-  dictionary InnerType {
-    // Documentation for the String s.
-    DOMString s;
-
-    // Documentation for the boolean b.
-    int b;
-
-    // Documentation for the int i.
-    int i;
-
-    // Documentation for the long l.
-    long l;
-
-    // Documentation for the double d.
-    double d;
-
-    // Documentation for the file entry f.
-    [instanceOf=FileEntry] object f;
-
-    // Documentation for the optional String s.
-    DOMString? os;
-
-    // Documentation for the optional boolean ob.
-    int ob;
-
-    // Documentation for the optional int i.
-    int? oi;
-
-    // Documentation for the optional long l.
-    long? ol;
-
-    // Documentation for the optional double d.
-    double? od;
-
-    // Documentation for the optional file entry f.
-    [instanceOf=FileEntry] object? of;
-  };
-
-  dictionary OuterType {
-    // Documentation for the array of InnerTypes items.
-    InnerType[] items;
-
-    // Documentation for the optional array of Inner Types oitems.
-    InnerType[]? oitems;
-  };
-
-  dictionary ComplexType {
-    // Documentation for the int i.
-    int i;
-
-    // Documentation for the ComplexType c.
-    ComplexType c;
-  };
-};