Move ExtensionSystem into extensions namespace

chrome/browser/sync/profile_sync_components_factory_impl.h

Index: chrome/browser/sync/profile_sync_components_factory_impl.h
diff --git a/chrome/browser/sync/profile_sync_components_factory_impl.h b/chrome/browser/sync/profile_sync_components_factory_impl.h
index 841ad171a77c19b10f9de2faa507fb506b05d3bd..ad1f15bf848340f2ed32e565973a6773974513df 100644
--- a/chrome/browser/sync/profile_sync_components_factory_impl.h
+++ b/chrome/browser/sync/profile_sync_components_factory_impl.h
@@ -14,9 +14,12 @@
 #include "chrome/browser/webdata/web_data_service.h"
 
 class CommandLine;
-class ExtensionSystem;
 class Profile;
 
+namespace extensions {
+class ExtensionSystem;
+}
+
 class ProfileSyncComponentsFactoryImpl : public ProfileSyncComponentsFactory {
  public:
   ProfileSyncComponentsFactoryImpl(Profile* profile,
@@ -66,7 +69,7 @@ class ProfileSyncComponentsFactoryImpl : public ProfileSyncComponentsFactory {
   CommandLine* command_line_;
   // Set on the UI thread (since ExtensionSystemFactory is non-threadsafe);
   // accessed on both the UI and FILE threads in GetSyncableServiceForType.
-  ExtensionSystem* extension_system_;
+  extensions::ExtensionSystem* extension_system_;
   scoped_refptr<WebDataService> web_data_service_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileSyncComponentsFactoryImpl);