Add chrome/browser/extensions to "GN check"

chrome/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/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
@@ skipping 95 matching lines @@
     "//components/crx_file",
     "//components/data_reduction_proxy/core/browser",
     "//components/data_usage/core",
     "//components/data_use_measurement/core",
     "//components/device_event_log",
     "//components/domain_reliability",
     "//components/favicon/core",
     "//components/favicon_base",
     "//components/flags_ui",
     "//components/gcm_driver",
-    "//components/gcm_driver/instance_id",
     "//components/google/core/browser",
     "//components/guest_view/browser",
     "//components/handoff",
     "//components/history/core/browser",
     "//components/history/core/common",
     "//components/infobars/core",
     "//components/invalidation/impl",
     "//components/metrics:gpu",
     "//components/metrics:net",
     "//components/metrics:profiler",
@@ skipping 1228 matching lines @@
   # linking all of the test support.
   static_library("pepper_cdm_test_constants") {
     testonly = true
     visibility = [ "//chrome/*" ]
     sources = [
       "media/pepper_cdm_test_constants.cc",
       "media/pepper_cdm_test_constants.h",
     ]
   }
 }