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

chrome/browser/extensions/extension_system_factory.cc

Index: chrome/browser/extensions/extension_system_factory.cc
diff --git a/chrome/browser/extensions/extension_system_factory.cc b/chrome/browser/extensions/extension_system_factory.cc
new file mode 100644
index 0000000000000000000000000000000000000000..5c5cc70eccd92893e419072f9363b33d80aae497
--- /dev/null
+++ b/chrome/browser/extensions/extension_system_factory.cc
@@ -0,0 +1,88 @@
+// Copyright (c) 2012 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.
+
+#include "chrome/browser/extensions/extension_system_factory.h"
+
+#include "chrome/browser/extensions/extension_message_service.h"
+#include "chrome/browser/extensions/extension_prefs.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/extensions/extension_system.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_dependency_manager.h"
+
+// ExtensionSystemDelegateFactory
+
+// static
+ExtensionSystemImpl::Delegate* ExtensionSystemDelegateFactory::GetForProfile(
+    Profile* profile) {
+  return static_cast<ExtensionSystemImpl::Delegate*>(
+      GetInstance()->GetServiceForProfile(profile, true));
+}
+
+// static
+ExtensionSystemDelegateFactory* ExtensionSystemDelegateFactory::GetInstance() {
+  return Singleton<ExtensionSystemDelegateFactory>::get();
+}
+
+ProfileKeyedService* ExtensionSystemDelegateFactory::BuildServiceInstanceFor(
+    Profile* profile) const {
+  return new ExtensionSystemImpl::Delegate(profile->GetOriginalProfile());

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

Since this is redirected in incognito, I'm pretty sure you'll be passed the
original profile.

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

Done.

+}
+
+bool ExtensionSystemDelegateFactory::ServiceRedirectedInIncognito() {
+  return true;
+}
+
+void ExtensionSystemDelegateFactory::ProfileShutdown(Profile* profile) {
+  if (GetForProfile(profile)->message_service())
+    GetForProfile(profile)->message_service()->DestroyingProfile();

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

You probably want this in you ExtensionService::Shutdown() method instead. You
won't need to override ProfileShutdown() here. (I never thought of using
GetForProfile() here and wonder if it is safe...)

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

Ah... I didn't read profile_keyed_service.h. This would make a *lot* more sense.

+  ProfileKeyedServiceFactory::ProfileShutdown(profile);
+}
+
+ExtensionSystemDelegateFactory::ExtensionSystemDelegateFactory()
+    : ProfileKeyedServiceFactory(
+        "ExtensionSystemDelegate",
+        ProfileDependencyManager::GetInstance()) {

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

I assume that either ExtensionSystemDelegateFactory or ExtensionSystemFactory is
going to depend on a lot of different systems. Please add commented out lines in
one of these constructors that are DependsOn() statments for them. (See
profile_sync_service_factory.cc as an example.)

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

I only found reference to 3 factories, all from ExtensionService. I added them
here.

+}
+
+ExtensionSystemDelegateFactory::~ExtensionSystemDelegateFactory() {
+}
+
+// ExtensionSystemFactory
+
+// static
+ExtensionSystem* ExtensionSystemFactory::GetForProfile(
+    Profile* profile) {
+  return static_cast<ExtensionSystem*>(
+      GetInstance()->GetServiceForProfile(profile, true));
+}
+
+// static
+ExtensionSystemFactory* ExtensionSystemFactory::GetInstance() {
+  return Singleton<ExtensionSystemFactory>::get();
+}
+
+ProfileKeyedService* ExtensionSystemFactory::BuildServiceInstanceFor(
+    Profile* profile) const {
+  return new ExtensionSystemImpl(profile);
+}
+
+bool ExtensionSystemFactory::ServiceHasOwnInstanceInIncognito() {
+  return true;
+}
+
+void ExtensionSystemFactory::ProfileShutdown(Profile* profile) {
+  GetForProfile(profile)->DestroyProcessManager();

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

Same as above.

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

Done.

+  ProfileKeyedServiceFactory::ProfileShutdown(profile);
+}
+
+ExtensionSystemFactory::ExtensionSystemFactory()
+    : ProfileKeyedServiceFactory(
+        "ExtensionSystem",
+        ProfileDependencyManager::GetInstance()) {
+  DependsOn(ExtensionSystemDelegateFactory::GetInstance());
+}
+
+ExtensionSystemFactory::~ExtensionSystemFactory() {
+}