Reland of Further reduction of feature_compiler.py generated code

extensions/common/features/base_feature_provider.cc

Index: extensions/common/features/base_feature_provider.cc
diff --git a/extensions/common/features/base_feature_provider.cc b/extensions/common/features/base_feature_provider.cc
index adc463cc04e9b6a54542995d055c5aee1ec860b6..26a4e740b9e1c660348ae733bacb3d75006b58eb 100644
--- a/extensions/common/features/base_feature_provider.cc
+++ b/extensions/common/features/base_feature_provider.cc
@@ -66,4 +66,8 @@
   features_[name.as_string()] = std::move(feature);
 }
 
+void BaseFeatureProvider::AddFeature(base::StringPiece name, Feature* feature) {
+  features_[name.as_string()] = std::unique_ptr<Feature>(feature);
+}
+
 }  // namespace extensions