Mojo: Remove url type converters.

mojo/common/url_type_converters.h

-// 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.
-
-#ifndef MOJO_COMMON_URL_TYPE_CONVERTERS_H_
-#define MOJO_COMMON_URL_TYPE_CONVERTERS_H_
-
-#include "mojo/public/cpp/bindings/string.h"
-#include "mojo/public/cpp/bindings/type_converter.h"
-
-class GURL;
-
-namespace mojo {
-
-template <>
-struct TypeConverter<String, GURL> {
-  static String Convert(const GURL& input);
-};
-
-template <>
-struct TypeConverter<GURL, String> {
-  static GURL Convert(const String& input);
-};
-
-}  // namespace mojo
-
-#endif  // MOJO_COMMON_URL_TYPE_CONVERTERS_H_