Change AuthenticatingURLLoader to be a URLLoaderInterceptor

shell/authenticating_url_loader_loader.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 SHELL_AUTHENTICATING_URL_LOADER_LOADER_H_
-#define SHELL_AUTHENTICATING_URL_LOADER_LOADER_H_
-
-#include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
-#include "mojo/public/cpp/application/application_impl.h"
-#include "services/authenticating_url_loader/authenticating_url_loader_app.h"
-#include "shell/application_manager/application_loader.h"
-
-namespace shell {
-
-class AuthenticatingURLLoaderLoader : public ApplicationLoader {
- public:
-  AuthenticatingURLLoaderLoader();
-  ~AuthenticatingURLLoaderLoader() override;
-
- private:
-  // ApplicationLoader overrides:
-  void Load(
-      const GURL& url,
-      mojo::InterfaceRequest<mojo::Application> application_request) override;
-
-  mojo::AuthenticatingURLLoaderApp authenticating_url_loader_;
-  scoped_ptr<mojo::ApplicationImpl> application_;
-
-  DISALLOW_COPY_AND_ASSIGN(AuthenticatingURLLoaderLoader);
-};
-
-}  // namespace shell
-
-#endif  // SHELL_AUTHENTICATING_URL_LOADER_LOADER_H_