Fix Autofill crash on mac address book entries

components/autofill/core/browser/personal_data_manager.h

Index: components/autofill/core/browser/personal_data_manager.h
diff --git a/components/autofill/core/browser/personal_data_manager.h b/components/autofill/core/browser/personal_data_manager.h
index a63b318f32ec8abeb2a0dac2f2888795e1831c18..f1fc9c17acad78e7807ea2449c2a1448bd5bef63 100644
--- a/components/autofill/core/browser/personal_data_manager.h
+++ b/components/autofill/core/browser/personal_data_manager.h
@@ -82,7 +82,8 @@ class PersonalDataManager : public KeyedService,
                       scoped_ptr<CreditCard>* credit_card);
 
   // Called to indicate |data_model| was used (to fill in a form). Updates
-  // the database accordingly.
+  // the database accordingly. Can invalidate |data_model|, particularly if
+  // it's a Mac address book entry.
   virtual void RecordUseOf(const AutofillDataModel& data_model);
 
   // Saves |imported_profile| to the WebDB if it exists. Returns the guid of