[iOS] More provider API for data reduction proxy settings

ios/public/test/test_keyed_service_provider.cc

Index: ios/public/test/test_keyed_service_provider.cc
diff --git a/ios/public/test/test_keyed_service_provider.cc b/ios/public/test/test_keyed_service_provider.cc
index 7c810e6d6dbbec8247c38118b947e9604ea9d022..068b6ebca7eeaed3a3c7e47c998c30b32d75dccf 100644
--- a/ios/public/test/test_keyed_service_provider.cc
+++ b/ios/public/test/test_keyed_service_provider.cc
@@ -107,6 +107,11 @@ TestKeyedServiceProvider::GetProfileInvalidationProviderForBrowserState(
   return nullptr;
 }
 
+KeyedServiceBaseFactory*
+TestKeyedServiceProvider::GetDataReductionProxySettingsFactory() {
+  return MissingServiceKeyedServiceFactory::GetInstance();
+}
+
 data_reduction_proxy::DataReductionProxySettings*
 TestKeyedServiceProvider::GetDataReductionProxySettingsForBrowserState(
     ios::ChromeBrowserState* browser_state) {