Add brotli content-encoding filter.

net/filter/brotli_filter.h

Index: net/filter/brotli_filter.h
diff --git a/net/filter/brotli_filter.h b/net/filter/brotli_filter.h
new file mode 100644
index 0000000000000000000000000000000000000000..5570ae4320e06e9edad355e1cbb700ce9d4e31aa
--- /dev/null
+++ b/net/filter/brotli_filter.h
@@ -0,0 +1,17 @@
+// 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_FILTER_BROTLI_FILTER_H_
+#define NET_FILTER_BROTLI_FILTER_H_
+
+#include "net/filter/filter.h"
+
+namespace net {
+
+// Creates instance of filter or returns nullptr if brotli is not supported.
+Filter* CreateBrotliFilter(Filter::FilterType type_id);
+
+}  // namespace net
+
+#endif  // NET_FILTER_BROTLI_FILTER_H__