mojo: first take on removing mojo_main_{chromium,standalone}.

mojo/services/view_manager/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/system.gni")
 
 component("view_manager") {
   deps = [
     "//base",
     "//cc",
     "//mojo/cc",
     "//mojo/common",
-    "//mojo/environment:chromium",
     "//mojo/public/cpp/application:chromium",
-    "//mojo/public/cpp/application:main_chromium",
     "//mojo/public/gles2",
     "//mojo/services/public/cpp/geometry",
     "//mojo/services/public/cpp/input_events",
     "//mojo/services/public/cpp/view_manager:common",
     "//mojo/services/public/interfaces/geometry",
     "//mojo/services/public/interfaces/input_events",
     "//mojo/services/public/interfaces/native_viewport",
     "//mojo/services/public/interfaces/view_manager",
     "//skia",
     "//ui/aura",
@@ skipping 37 matching lines @@
     "view_manager_init_service_impl.cc",
     "view_manager_init_service_impl.h",
     "view_manager_service_impl.cc",
     "view_manager_service_impl.h",
     "window_manager_access_policy.cc",
     "window_manager_access_policy.h",
     "window_tree_host_impl.cc",
     "window_tree_host_impl.h",
   ]
 }