Remove stl_util's STLDeleteContainerPairSecondPointers from extensions.

extensions/browser/api/vpn_provider/vpn_service.h

Index: extensions/browser/api/vpn_provider/vpn_service.h
diff --git a/extensions/browser/api/vpn_provider/vpn_service.h b/extensions/browser/api/vpn_provider/vpn_service.h
index 664c0cc538dfe5b06d76494ae89e7f1a41e060c2..0e2f1d78cf45912a94a54bb5a10d12a4c4864960 100644
--- a/extensions/browser/api/vpn_provider/vpn_service.h
+++ b/extensions/browser/api/vpn_provider/vpn_service.h
@@ -173,6 +173,8 @@ class VpnService : public KeyedService,
   class VpnServiceProxyImpl;
 
   using StringToConfigurationMap = std::map<std::string, VpnConfiguration*>;
+  using StringToOwnedConfigurationMap =
+      std::map<std::string, std::unique_ptr<VpnConfiguration>>;
 
   // Callback used to indicate that configuration was successfully created.
   void OnCreateConfigurationSuccess(const SuccessCallback& callback,
@@ -253,8 +255,7 @@ class VpnService : public KeyedService,
 
   VpnConfiguration* active_configuration_;
 
-  // Key map owns the VpnConfigurations.
-  StringToConfigurationMap key_to_configuration_map_;
+  StringToOwnedConfigurationMap key_to_configuration_map_;
 
   // Service path does not own the VpnConfigurations.
   StringToConfigurationMap service_path_to_configuration_map_;