Remove duplicated user_prefs::TestingPrefServiceSyncable

components/content_settings/core/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/features.gni")
 import("//ppapi/features/features.gni")
 
 static_library("browser") {
   sources = [
     "content_settings_binary_value_map.cc",
@@ skipping 65 matching lines @@
   if (enable_plugins) {
     sources += [ "content_settings_provider_unittest.cc" ]
   }
 
   deps = [
     ":browser",
     "//base",
     "//base/test:test_support",
     "//components/content_settings/core/common",
     "//components/content_settings/core/test:test_support",
-    "//components/pref_registry:test_support",
+    "//components/pref_registry:pref_registry",
     "//components/prefs",
+    "//components/sync_preferences:test_support",
     "//extensions/features",
     "//testing/gtest",
     "//url",
   ]
 }