Split WarningService from ExtensionSystem.

extensions/browser/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/crypto.gni")
 import("//build/config/features.gni")
 
 # GYP version: extensions/extensions.gyp:extensions_browser
 source_set("browser") {
   sources = [
@@ skipping 462 matching lines @@
       "value_store/value_store_frontend.cc",
       "value_store/value_store_frontend.h",
       "value_store/value_store_util.cc",
       "value_store/value_store_util.h",
       "verified_contents.cc",
       "verified_contents.h",
       "view_type_utils.cc",
       "view_type_utils.h",
       "warning_service.cc",
       "warning_service.h",
+      "warning_service_factory.cc",
+      "warning_service_factory.h",
       "warning_set.cc",
       "warning_set.h",
     ]
 
     deps += [
       "//components/storage_monitor",
       "//crypto:platform",
       "//device/bluetooth",
       "//device/core",
       "//device/hid",
@@ skipping 12 matching lines @@
       ]
     }
   }
 
   if (is_win) {
     cflags = [
       "/wd4267", # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     ]
   }
 }