Implement "streaming" $i18n{} replacer

net/filter/filter.h

Index: net/filter/filter.h
diff --git a/net/filter/filter.h b/net/filter/filter.h
index 1940399e06806095796380a91054db20186e7837..3300a2e6d6b20e11cdd0c1916a8226d04ec1ae3b 100644
--- a/net/filter/filter.h
+++ b/net/filter/filter.h
@@ -239,6 +239,10 @@ class NET_EXPORT Filter {
 
   FilterType type() const { return type_id_; }
 
+  // Sets |next_filter| as the next filter to be run, disconnecting any existing
+  // chain.
+  void TakeNextFilter(std::unique_ptr<Filter> next_filter);
+
  protected:
   friend class BrotliUnitTest;
   friend class GZipUnitTest;