WORK IN PROGRESS.

chrome/browser/sync/profile_sync_factory_impl.cc

Index: chrome/browser/sync/profile_sync_factory_impl.cc
diff --git a/chrome/browser/sync/profile_sync_factory_impl.cc b/chrome/browser/sync/profile_sync_factory_impl.cc
index 9188f7ff8c3c0318d04860b1cc2cdac174c1120f..6fc1e9aa2698006e6d7615af187b5df7073490c1 100644
--- a/chrome/browser/sync/profile_sync_factory_impl.cc
+++ b/chrome/browser/sync/profile_sync_factory_impl.cc
@@ -4,6 +4,7 @@
 
 #include "base/command_line.h"
 #include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/extensions/extension_settings.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/api/syncable_service.h"
 #include "chrome/browser/sync/glue/app_change_processor.h"
@@ -22,6 +23,7 @@
 #include "chrome/browser/sync/glue/extension_change_processor.h"
 #include "chrome/browser/sync/glue/extension_data_type_controller.h"
 #include "chrome/browser/sync/glue/extension_model_associator.h"
+#include "chrome/browser/sync/glue/extension_setting_data_type_controller.h"
 #include "chrome/browser/sync/glue/extension_sync_traits.h"
 #include "chrome/browser/sync/glue/generic_change_processor.h"
 #include "chrome/browser/sync/glue/password_change_processor.h"
@@ -64,6 +66,7 @@ using browser_sync::DataTypeManagerImpl;
 using browser_sync::ExtensionChangeProcessor;
 using browser_sync::ExtensionDataTypeController;
 using browser_sync::ExtensionModelAssociator;
+using browser_sync::ExtensionSettingDataTypeController;
 using browser_sync::GenericChangeProcessor;
 using browser_sync::PasswordChangeProcessor;
 using browser_sync::PasswordDataTypeController;
@@ -159,6 +162,13 @@ void ProfileSyncFactoryImpl::RegisterDataTypes(ProfileSyncService* pss) {
         new SessionDataTypeController(this, profile_, pss));
   }
 
+  // Extension setting sync is disabled by default.  Register only if
+  // explicitly enabled.
+  if (command_line_->HasSwitch(switches::kEnableSyncExtensionSettings)) {
+    pss->RegisterDataTypeController(
+        new ExtensionSettingDataTypeController(this, profile_, pss));
+  }
+
   if (!command_line_->HasSwitch(switches::kDisableSyncAutofillProfile)) {
     pss->RegisterDataTypeController(
         new AutofillProfileDataTypeController(this, profile_));
@@ -244,6 +254,22 @@ ProfileSyncFactoryImpl::CreateBookmarkSyncComponents(
 }
 
 ProfileSyncFactory::SyncComponents
+ProfileSyncFactoryImpl::CreateExtensionSettingSyncComponents(
+    ProfileSyncService* profile_sync_service,
+    UnrecoverableErrorHandler* error_handler) {
+  SyncableService* sync_service =
+      profile_->GetExtensionService()->extension_settings();
+  sync_api::UserShare* user_share = profile_sync_service->GetUserShare();
+  GenericChangeProcessor* change_processor =
+      new GenericChangeProcessor(sync_service, error_handler, user_share);
+  browser_sync::SyncableServiceAdapter* sync_service_adapter =
+      new browser_sync::SyncableServiceAdapter(syncable::EXTENSION_SETTINGS,
+                                               sync_service,
+                                               change_processor);
+  return SyncComponents(sync_service_adapter, change_processor);
+}
+
+ProfileSyncFactory::SyncComponents
 ProfileSyncFactoryImpl::CreateExtensionSyncComponents(
     ProfileSyncService* profile_sync_service,
     UnrecoverableErrorHandler* error_handler) {