Moving gRPC support interfaces out of cronet and into a new component.

components/cronet/ios/cronet_environment.cc

 // 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.
 
 #include "components/cronet/ios/cronet_environment.h"
 
 #include <utility>
 
 #include "base/at_exit.h"
 #include "base/atomicops.h"
@@ skipping 322 matching lines @@
       new net::HttpCache(http_network_session, std::move(main_backend),
                          true /* set_up_quic_server_info */);
   main_context_->set_http_transaction_factory(main_cache);
 
   net::URLRequestJobFactoryImpl* job_factory =
       new net::URLRequestJobFactoryImpl;
   main_context_->set_job_factory(job_factory);
   main_context_->set_net_log(net_log_.get());
 }
 
-std::string CronetEnvironment::user_agent() {
+std::string CronetEnvironment::UserAgent() {
   const net::HttpUserAgentSettings* user_agent_settings =
       main_context_->http_user_agent_settings();
   if (!user_agent_settings) {
     return nullptr;
   }
 
   return user_agent_settings->GetUserAgent();
 }
 
 }  // namespace cronet