Try to flush DOMStorage too when ending the browsing session.

chrome/browser/browsing_data/browsing_data_remover_impl_unittest.cc

Index: chrome/browser/browsing_data/browsing_data_remover_impl_unittest.cc
diff --git a/chrome/browser/browsing_data/browsing_data_remover_impl_unittest.cc b/chrome/browser/browsing_data/browsing_data_remover_impl_unittest.cc
index 53518b5ead71b2a08532af400541c7080ad78098..5c09b26f68a8b65c9a6c8db08fac226957e5eeb0 100644
--- a/chrome/browser/browsing_data/browsing_data_remover_impl_unittest.cc
+++ b/chrome/browser/browsing_data/browsing_data_remover_impl_unittest.cc
@@ -234,7 +234,9 @@ class TestStoragePartition : public StoragePartition {
     // Not needed in this test.
   }
 
-  void Flush() override {}
+  std::vector<scoped_refptr<base::SequencedTaskRunner>> Flush() override {
+    return std::vector<scoped_refptr<base::SequencedTaskRunner>>();
+  }
 
   void ClearBluetoothAllowedDevicesMapForTesting() override {}