Add brotli content-encoding filter.

net/http/http_features.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef NET_HTTP_HTTP_FEATURES_H_
+#define NET_HTTP_HTTP_FEATURES_H_
+
+// This file defines all the base::FeatureList features for the net module.
+
+#include "base/feature_list.h"
+
+namespace net {
+
+namespace features {
+
+// All features in alphabetical order. The features should be documented
+// alongside the definition of their values in the .cc file.
+extern const base::Feature kBrotliEncodingFeature;
+
+// Checks if brotli encoding feature is enabled and supported.
+bool IsBrotliEncodingEnabled();
+
+}  // namespace features
+
+}  // namespace net
+
+#endif  // NET_HTTP_HTTP_FEATURES_H_