Move the supervised user error page to a component

components/supervised_user_error_page/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.
 
-static_library("child") {
+source_set("supervised_user_error_page") {
   sources = [
-    "pdf_child_init.cc",
-    "pdf_child_init.h",
+    "supervised_user_error_page.cc",
+    "supervised_user_error_page.h",
   ]
 
-  configs += [ "//build/config/compiler:wexit_time_destructors" ]
-
   deps = [
     "//base",
-    "//content/public/child",
+    "//components/resources",
+    "//components/strings",
+    "//ui/base",
   ]
 }