Componentize PrefSyncableService and support classes.

chrome/browser/BUILD.gn

Index: chrome/browser/BUILD.gn
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 59ea9d973546988b9999b41425587d56a2c4a7f2..cefe99b763cc0708f20a711f6e10569ed694dde1 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -291,6 +291,7 @@ source_set("browser") {
       "//components/safe_json",
       "//components/sessions",
       "//components/storage_monitor",
+      "//components/syncable_prefs",
       "//components/translate/content/browser",
       "//components/upload_list",
       "//components/url_matcher",
@@ -1040,8 +1041,6 @@ source_set("test_support") {
     "password_manager/password_manager_test_base.h",
     "password_manager/test_password_store_service.cc",
     "password_manager/test_password_store_service.h",
-    "prefs/pref_service_mock_factory.cc",
-    "prefs/pref_service_mock_factory.h",
     "profile_resetter/profile_resetter_test_base.cc",
     "profile_resetter/profile_resetter_test_base.h",
     "search_engines/template_url_service_factory_test_util.cc",
@@ -1085,6 +1084,7 @@ source_set("test_support") {
     "//components/invalidation/impl:test_support",
     "//components/password_manager/core/browser:test_support",
     "//components/search_engines:test_support",
+    "//components/syncable_prefs:test_support",
     "//components/user_prefs/tracked:user_prefs_tracked_test_support",
     "//content/test:test_support",
     "//chrome/app/theme:theme_resources",