Remove mojo:: part of mojo::shell:: nested namespace in //shell.

shell/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("//build/config/ui.gni")
 import("//mojo/public/mojo.gni")
 import("//mojo/public/mojo_application.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//mojo/tools/embed/rules.gni")
 import("//testing/test.gni")
@@ skipping 420 matching lines @@
   deps = [
     ":lib",
     "//base",
     "//mojo/edk/system",
     "//shell/application_manager",
   ]
 }
 
 embed_file("embed_pingable") {
   source = "$root_build_dir/pingable_app.mojo"
-  namespace = "mojo"
+  namespace = "shell::test"
   variable = "kPingable"
   testonly = true
 
   deps = [
     "//shell/test:pingable_app",
   ]
 }
 
 mojo_native_application("apptests") {
   output_name = "shell_apptests"
@@ skipping 14 matching lines @@
     "//mojo/public/cpp/system:system",
     "//mojo/services/http_server/public/cpp",
     "//mojo/services/http_server/public/interfaces",
     "//mojo/services/network/public/interfaces",
     "//shell/test:bindings",
     ":embed_pingable",
   ]
 
   data_deps = [ "//services/http_server:http_server($default_toolchain)" ]
 }