Add migration code to change existing domain scoped content settings to be origin scoped

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")
 
 source_set("browser") {
   sources = [
     "content_settings_binary_value_map.cc",
     "content_settings_binary_value_map.h",
@@ skipping 41 matching lines @@
       "plugins_field_trial.h",
     ]
   }
 
   deps = [
     "//base",
     "//components/content_settings/core/common",
     "//components/keyed_service/core",
     "//components/pref_registry:pref_registry",
     "//components/prefs",
+    "//components/syncable_prefs",
     "//components/url_formatter",
     "//net",
     "//url",
   ]
 
   configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 }
 
 source_set("unit_tests") {
   testonly = true
@@ skipping 16 matching lines @@
     "//base",
     "//base/test:test_support",
     "//components/content_settings/core/common",
     "//components/content_settings/core/test:test_support",
     "//components/pref_registry:test_support",
     "//components/prefs",
     "//testing/gtest",
     "//url",
   ]
 }