Move //mojo/services/X/public/... to //mojo/services/X/... (part 1).

mojo/services/content_handler/interfaces/content_handler.mojom

 // 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.
 
 [DartPackage="mojo_services"]
 module mojo;
 
 import "mojo/public/interfaces/application/application.mojom";
 import "mojo/public/interfaces/network/url_response.mojom";
 
 interface ContentHandler {
   StartApplication(Application& application, URLResponse response);
 };