Move the JS content handler et al from mojo/apps/js to mojo/services

mojo/apps/js/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.
-
-group("js") {
-  # Meta-target, don't link into production code.
-  testonly = true
-  deps = [
-    ":js_content_handler",
-  ]
-}
-
-source_set("js_apps") {
-  sources = [
-    "js_app.cc",
-    "mojo_bridge_module.cc",
-  ]
-
-  public_deps = [
-    "//mojo/edk/js",
-  ]
-  deps = [
-    "//mojo/application",
-    "//mojo/public/c/system:for_shared_library",
-    "//mojo/public/cpp/utility",
-  ]
-}
-
-shared_library("js_content_handler") {
-  sources = [
-    "content_handler_main.cc",
-  ]
-
-  deps = [
-    ":js_apps",
-    "//base:i18n",
-    "//mojo/application:application",
-    "//mojo/application:content_handler",
-    "//mojo/environment:chromium",
-    "//mojo/services/public/interfaces/content_handler",
-  ]
-}