Split ExtensionSystem interface from ExtensionSystemImpl implementation, part 1.

chrome/browser/extensions/extension_sync_service_factory.cc

Index: chrome/browser/extensions/extension_sync_service_factory.cc
diff --git a/chrome/browser/extensions/extension_sync_service_factory.cc b/chrome/browser/extensions/extension_sync_service_factory.cc
index 2d3aee9d2eca8fe69a77fd3cf3c5bb49e0de22e7..1e8629c4217d5592af8e30ed931bbdbb5f0acf84 100644
--- a/chrome/browser/extensions/extension_sync_service_factory.cc
+++ b/chrome/browser/extensions/extension_sync_service_factory.cc
@@ -6,12 +6,12 @@
 
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/extensions/extension_sync_service.h"
-#include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/extensions/extension_system_factory.h"
 #include "chrome/browser/profiles/incognito_helpers.h"
 #include "chrome/browser/profiles/profile.h"
 #include "components/browser_context_keyed_service/browser_context_dependency_manager.h"
 #include "extensions/browser/extension_prefs_factory.h"
+#include "extensions/browser/extension_system.h"
 
 // static
 ExtensionSyncService* ExtensionSyncServiceFactory::GetForProfile(
@@ -42,8 +42,7 @@ BrowserContextKeyedService*
   return new ExtensionSyncService(
       profile,
       extensions::ExtensionPrefsFactory::GetForBrowserContext(context),
-      extensions::ExtensionSystemFactory::GetForProfile(profile)->
-          extension_service());
+      extensions::ExtensionSystem::Get(profile)->extension_service());
 }
 
 content::BrowserContext* ExtensionSyncServiceFactory::GetBrowserContextToUse(