MD Settings: fix crash from strongly bound handler that goes away

chrome/browser/ui/webui/settings/profile_info_handler.h

Index: chrome/browser/ui/webui/settings/profile_info_handler.h
diff --git a/chrome/browser/ui/webui/settings/profile_info_handler.h b/chrome/browser/ui/webui/settings/profile_info_handler.h
index 6aa21f0e8b99773e1b0e6c3dc7356c548f70f9cb..5050e5b3adee00e00c01cd3e8ea0c6f6134d742a 100644
--- a/chrome/browser/ui/webui/settings/profile_info_handler.h
+++ b/chrome/browser/ui/webui/settings/profile_info_handler.h
@@ -8,6 +8,7 @@
 #include <memory>
 
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "base/scoped_observer.h"
 #include "build/build_config.h"
 #include "chrome/browser/profiles/profile_attributes_storage.h"
@@ -95,6 +96,8 @@ class ProfileInfoHandler : public SettingsPageUIHandler,
   // Used to listen for changes in the list of managed supervised users.
   PrefChangeRegistrar profile_pref_registrar_;
 
+  base::WeakPtrFactory<ProfileInfoHandler> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(ProfileInfoHandler);
 };