Add chrome/browser/extensions to "GN check"

components/spellcheck/browser/BUILD.gn

 # Copyright 2016 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.
 
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
 source_set("browser") {
   sources = [
@@ skipping 16 matching lines @@
     "spellcheck_platform_android.cc",
     "spellcheck_platform_mac.mm",
     "spellchecker_session_bridge_android.cc",
     "spellchecker_session_bridge_android.h",
     "spelling_service_client.cc",
     "spelling_service_client.h",
     "word_trimmer.cc",
     "word_trimmer.h",
   ]
 
+  public_deps = [
+    "//base",
+    "//components/spellcheck/common",
+  ]
   deps = [
-    "//base",
-    "//components/data_use_measurement/core:core",
-    "//components/prefs:prefs",
-    "//components/spellcheck/common",
-    "//components/user_prefs:user_prefs",
+    "//components/data_use_measurement/core",
+    "//components/prefs",
+    "//components/user_prefs",
     "//content/public/browser",
     "//content/public/common",
-    "//google_apis:google_apis",
-    "//net:net",
+    "//google_apis",
+    "//net",
   ]
 
   if (is_android) {
     sources += [
       "android/component_jni_registrar.cc",
       "android/component_jni_registrar.h",
     ]
     deps += [ "android:jni_headers" ]
   }
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
     "feedback_sender_unittest.cc",
     "feedback_unittest.cc",
     "misspelling_unittest.cc",
     "spellcheck_action_unittest.cc",
     "spellcheck_host_metrics_unittest.cc",
     "spellcheck_platform_mac_unittest.cc",
     "word_trimmer_unittest.cc",
   ]
 
   deps = [
     ":browser",
     "//base",
     "//base/test:test_support",
     "//components/spellcheck/common",
-    "//components/variations:variations",
+    "//components/variations",
     "//content/test:test_support",
     "//net:test_support",
     "//testing/gtest",
   ]
 }