Add remaining trivial targets for the Linux GN build

content/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("//tools/grit/grit_rule.gni")
 
 # Applied by targets internal to content.
 config("content_implementation") {
   defines = [ "CONTENT_IMPLEMENTATION" ]
 }
@@ skipping 62 matching lines @@
 }
 
 # This target exists to "hold" the content_export header so we can do proper
 # inclusion testing of it.
 source_set("export") {
   visibility = [ "//content/*" ]
   sources = [
     "content/common/content_export.h",
   ]
 }
+
+if (is_win) {
+  source_set("content_startup_helper_win") {
+    sources = [
+      "app/startup_helper_win.cc",
+      "public/app/startup_helper_win.h",
+    ]
+
+    deps = [
+      "//base",
+      "//base:i18n",
+      "//sandbox",
+    ]
+  }
+}