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

examples/content_handler_demo/BUILD.gn

 # 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.
 
 import("//mojo/public/mojo_application.gni")
 
 mojo_native_application("content_handler_demo") {
   sources = [
     "content_handler_demo.cc",
   ]
 
   deps = [
     "//mojo/public/cpp/application:standalone",
     "//mojo/public/cpp/bindings",
     "//mojo/public/cpp/utility",
-    "//mojo/services/content_handler/public/interfaces",
+    "//mojo/services/content_handler/interfaces",
   ]
 }