Take extensions out of Profile into a profile-keyed service, ExtensionSystem.

chrome/browser/sync/glue/app_data_type_controller.cc

Index: chrome/browser/sync/glue/app_data_type_controller.cc
diff --git a/chrome/browser/sync/glue/app_data_type_controller.cc b/chrome/browser/sync/glue/app_data_type_controller.cc
index 327ca387cfac3bf85666a4f45306fe8fe591ef59..f177ce43b410008ea1339421b409b1db1453836b 100644
--- a/chrome/browser/sync/glue/app_data_type_controller.cc
+++ b/chrome/browser/sync/glue/app_data_type_controller.cc
@@ -5,6 +5,8 @@
 #include "chrome/browser/sync/glue/app_data_type_controller.h"
 
 #include "base/metrics/histogram.h"
+#include "chrome/browser/extensions/extension_system.h"
+#include "chrome/browser/extensions/extension_system_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/profile_sync_components_factory.h"
 
@@ -27,7 +29,7 @@ syncable::ModelType AppDataTypeController::type() const {
 }
 
 bool AppDataTypeController::StartModels() {
-  profile_->InitExtensions(true);
+  ExtensionSystemFactory::GetForProfile(profile_)->Init(true);

[Elliot Glaysher, 2012/02/09 20:10:24]

This shouldn't be necessary; ExtensionService should be depended on by the whole
ProfileSyncService; you just need to uncomment the DependsOn line in
profile_sync_service_factory.cc.

[Yoyo Zhou, 2012/02/16 21:49:20]

This is actually calling InitExtensions, which can't be done easily in
BuildServiceInstanceFor because it takes an argument here. (I briefly looked
into refactoring it to not take the argument, but it seemed not too
straightforward.)

   return true;
 }