Remove extraneous datadep from html_viewer

mojo/services/html_viewer/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.gni")
 import("//mojo/public/mojo_application.gni")
 
 # GYP version: mojo/mojo_services.gypi:html_viewer
 mojo_native_application("html_viewer") {
   sources = [
@@ skipping 57 matching lines @@
     "//mojo/services/public/interfaces/input_events:input_events",
     "//mojo/services/public/interfaces/navigation",
     "//mojo/services/public/interfaces/network",
     "//mojo/services/public/interfaces/surfaces",
     "//net",
     "//skia",
     "//third_party/WebKit/public:blink",
     "//ui/native_theme",
     "//url",
   ]
-
-  if (use_prebuilt_mojo_shell) {
-    datadeps = [ "//mojo/public/tools:copy_mojo_shell" ]
-  }
 }