Change ContentSettingsType's scoping type and hookup migration code

chrome/browser/content_settings/host_content_settings_map_factory.cc

Index: chrome/browser/content_settings/host_content_settings_map_factory.cc
diff --git a/chrome/browser/content_settings/host_content_settings_map_factory.cc b/chrome/browser/content_settings/host_content_settings_map_factory.cc
index a96b421a0b5b60922df8ae6d707b64ec12aa304b..bbe6d4d6331ecc4918c39efa2620a76ff1be40a1 100644
--- a/chrome/browser/content_settings/host_content_settings_map_factory.cc
+++ b/chrome/browser/content_settings/host_content_settings_map_factory.cc
@@ -6,10 +6,12 @@
 
 #include <utility>
 
+#include "chrome/browser/prefs/pref_service_syncable_util.h"
 #include "chrome/browser/profiles/off_the_record_profile_impl.h"
 #include "chrome/browser/profiles/profile.h"
 #include "components/content_settings/core/browser/host_content_settings_map.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
+#include "components/syncable_prefs/pref_service_syncable.h"
 #include "content/public/browser/browser_thread.h"
 
 #if defined(ENABLE_EXTENSIONS)
@@ -72,6 +74,14 @@ scoped_refptr<RefcountedKeyedService>
       profile->GetProfileType() == Profile::INCOGNITO_PROFILE,
       profile->GetProfileType() == Profile::GUEST_PROFILE));
 
+  syncable_prefs::PrefServiceSyncable* pref_service =
+      PrefServiceSyncableFromProfile(profile);
+  if (pref_service) {
+    pref_service->RegisterMergeDataFinishedCallback(
+        base::Bind(&HostContentSettingsMap::MigrateDomainScopedSettings,
+                   settings_map->GetWeakPtr()));
+  }
+
 #if defined(ENABLE_EXTENSIONS)
   ExtensionService *ext_service =
       extensions::ExtensionSystem::Get(profile)->extension_service();