Revert of [cronet] Expose API to set experimental options

components/cronet/ios/cronet_environment.h

 // Copyright 2016 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 COMPONENTS_CRONET_IOS_CRONET_ENVIRONMENT_H_
 #define COMPONENTS_CRONET_IOS_CRONET_ENVIRONMENT_H_
 
 #include <list>
 #include <string>
 #include <vector>
@@ skipping 73 matching lines @@
 
   void set_mock_cert_verifier(
       std::unique_ptr<net::CertVerifier> mock_cert_verifier) {
     mock_cert_verifier_ = std::move(mock_cert_verifier);
   }
 
   void set_http_cache(URLRequestContextConfig::HttpCacheType http_cache) {
     http_cache_ = http_cache;
   }
 
-  void set_experimental_options(const std::string& experimental_options) {
-    experimental_options_ = experimental_options;
-  }
-
   void SetHostResolverRules(const std::string& host_resolver_rules);
 
   void set_ssl_key_log_file_name(const std::string& ssl_key_log_file_name) {
     ssl_key_log_file_name_ = ssl_key_log_file_name;
   }
 
   // Returns the URLRequestContext associated with this object.
   net::URLRequestContext* GetURLRequestContext() const;
 
   // Return the URLRequestContextGetter associated with this object.
@@ skipping 23 matching lines @@
   // Sets host resolver rules on the network_io_thread_.
   void SetHostResolverRulesOnNetworkThread(const std::string& rules,
                                            base::WaitableEvent* event);
 
   std::string getDefaultQuicUserAgentId() const;
 
   bool http2_enabled_;
   bool quic_enabled_;
   std::string quic_user_agent_id_;
   std::string accept_language_;
-  std::string experimental_options_;
   std::string ssl_key_log_file_name_;
   URLRequestContextConfig::HttpCacheType http_cache_;
 
   std::list<net::HostPortPair> quic_hints_;
 
   std::unique_ptr<base::Thread> network_io_thread_;
   std::unique_ptr<base::Thread> network_cache_thread_;
   std::unique_ptr<base::Thread> file_thread_;
   std::unique_ptr<base::Thread> file_user_blocking_thread_;
   scoped_refptr<base::SequencedTaskRunner> pref_store_worker_pool_;
   std::unique_ptr<net::CertVerifier> mock_cert_verifier_;
   std::unique_ptr<net::CookieStore> cookie_store_;
   std::unique_ptr<net::URLRequestContext> main_context_;
   scoped_refptr<net::URLRequestContextGetter> main_context_getter_;
   std::string user_agent_;
   bool user_agent_partial_;
   std::unique_ptr<net::NetLog> net_log_;
   std::unique_ptr<net::WriteToFileNetLogObserver> net_log_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(CronetEnvironment);
 };
 
 }  // namespace cronet
 
 #endif  // COMPONENTS_CRONET_IOS_CRONET_ENVIRONMENT_H_