Add brotli content-encoding filter.

net/url_request/url_request_test_util.h

Index: net/url_request/url_request_test_util.h
diff --git a/net/url_request/url_request_test_util.h b/net/url_request/url_request_test_util.h
index 07728cbd0b4dad9dc0203deab4fc5b099c494669..574f8bd66ef3074fd7d2086a00917e1c76161099 100644
--- a/net/url_request/url_request_test_util.h
+++ b/net/url_request/url_request_test_util.h
@@ -296,6 +296,8 @@ class TestNetworkDelegate : public NetworkDelegateImpl {
     return last_observed_proxy_;
   }
 
+  const HttpRequestHeaders& last_headers() const { return last_headers_; }
+
   void set_can_be_intercepted_on_error(bool can_be_intercepted_on_error) {
     will_be_intercepted_on_next_error_ = can_be_intercepted_on_error;
   }
@@ -389,6 +391,8 @@ class TestNetworkDelegate : public NetworkDelegateImpl {
   bool experimental_cookie_features_enabled_;           // false by default
   bool cancel_request_with_policy_violating_referrer_;  // false by default
   bool will_be_intercepted_on_next_error_;
+
+  HttpRequestHeaders last_headers_;
 };
 
 //-----------------------------------------------------------------------------