Pref service: support for incognito prefs

services/preferences/persistent_pref_store_factory.cc

Index: services/preferences/persistent_pref_store_factory.cc
diff --git a/services/preferences/persistent_pref_store_factory.cc b/services/preferences/persistent_pref_store_factory.cc
index 587ac96d1828ed0ee3995e1f8cb911f595f94c70..352ebaf2bd6bd01582ecaba7e0e3a35f0d2c4491 100644
--- a/services/preferences/persistent_pref_store_factory.cc
+++ b/services/preferences/persistent_pref_store_factory.cc
@@ -7,6 +7,7 @@
 #include <memory>
 #include <utility>
 
+#include "components/prefs/in_memory_pref_store.h"
 #include "components/prefs/json_pref_store.h"
 #include "components/prefs/pref_filter.h"
 #include "services/preferences/persistent_pref_store_impl.h"
@@ -44,6 +45,10 @@ std::unique_ptr<PersistentPrefStoreImpl> CreatePersistentPrefStore(
             std::move(configuration->get_tracked_configuration()), worker_pool),
         std::move(on_initialized));
   }
+  if (configuration->is_incognito_configuration()) {
+    return base::MakeUnique<PersistentPrefStoreImpl>(new InMemoryPrefStore(),
+                                                     std::move(on_initialized));
+  }
   NOTREACHED();
   return nullptr;
 }